Errata in published sources

Implementing a standard clean-room means re-deriving every formula, constant and worked example from the source document rather than from anyone else’s code. Done across hundreds of documents, that process finds defects in the sources themselves: a worked example that contradicts its own normative clause, a constant with a digit dropped in typesetting, a cross-reference that points at the wrong equation.

This page is the registry of those findings. Each entry names the printed edition and the exact location, quotes what the document says, shows why it cannot be right, gives the independent evidence, and states which reading the library implements and which regression test pins it. A defect listed here is never a defect of the method: in every case the intended reading could be established from the document itself or from physics.

Read it alongside the conformance report, which shows the numbers the library computes; this page explains the handful of places where the printed expected value is the thing that is wrong.

The registry is maintained in docs/ERRATA.md and transplanted here at build time by make site-reports, so the two cannot disagree.

During the clean-room implementation of this library, every formula, constant and worked example is re-derived and recomputed independently from the source documents. That process occasionally surfaces defects in the sources themselves: misprints, worked examples that contradict their own normative text, and ambiguous wording. This file records each confirmed case with the evidence, what the library does about it, and whether it has been reported.

The registry covers every kind of published source the library implements from: standards (ISO, IEC, EN), guidance documents and technical reports (EASA, ECAC, NRL), textbooks and journal papers. Non-normative sources are marked as such in their entry.

Entries describe the specific printed editions cited. A defect listed here is not a defect of the method; in every case the intended reading could be established from the document itself or from physics, and the library implements that reading. Where the reading changes a number the library reports, the entry names the check or test that pins it; where the defect is a label, a cross-reference or a table the library never reads, the entry records that no change was required.

Status legend: unreported (recorded here only) / reported (submitted to the issuing body, with date and reference).

A claim that turns on the exact characters of a formula, constant, coefficient, symbol, inequality or table cell is verified against the page as printed, and its Evidence bullet cites that page by PDF page index and printed folio. Extracted text may locate a page; it is never quoted as “the print”, because PDF text layers delete glyphs silently (most of the sources cited here emit no √ at all, so f_T/√2 extracts as f_T/2). The page offset of each document is established empirically, because it differs per document and drifts between chapters of the same book. Entries that rest on something else, a recomputation or a comparison of two sentences, say so either in a leading notice or on the allowlist of scripts/check_errata_evidence.py, which is the check that enforces the rule; see CONTRIBUTING.md.

A Spanish edition of this registry, translated entry for entry, is maintained in ERRATA.es.md. The wording here is the authoritative one, and quoted print, mathematics and printed values are reproduced there untranslated; make site-reports holds the two editions to the same entries in the same order.

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• Location: Annex C, Table C.1 (printed p. 17) and the accompanying $C_I$ computation printed in the same cell.
• The print: $L_{n,\text{sum}}=83,5238\dots =84\text{dB}$ and $C_I=84-15-79=-10\text{dB}$ for the bare-floor example.
• The problem: two independent defects in the same cell. (a) Clause A.2.1 defines $C_I$ from the energy sum over 100 Hz to 2500 Hz (the first fifteen one-third-octave bands); the printed value only reproduces if the 3150 Hz band is included, contradicting A.2.1. The correct sum over 100 Hz to 2500 Hz is 83,2613 dB, rounded 83, giving $C_I=-11$. (b) Even read as the sixteen-band sum the printed digits are wrong in the last place: the bare-floor $L_n$ column sums to 83,523 4 dB, not the printed 83,523 8 dB. The defect is confined to that cell, since the with-covering column of the same table prints $L_{n,\text{sum}}=76,0593\dots$ and recomputes to 76,059 29 dB, reproducing every printed digit. Neither (a) nor (b) changes the rounded 84 dB, so only (a) moves $C_I$.
• Evidence: independent recomputation of both sums from the printed per-band levels (16 bands 83,523 38 dB, 15 bands 83,261 27 dB, with-covering 16 bands 76,059 29 dB); the 2013 edition of the same example prints $C_I=-11$. Verified on PDF page 23 (printed p. 17) and PDF page 17 (printed p. 11) of ISO 717-2:2020, and of PDF page 22 (printed p. 14) of ISO 717-2:2013.
• Library behaviour: implements A.2.1 as written and pins $C_I=-11$ with the 2013 print as the oracle (tests/reference_data/, conformance check “ISO 717-2 Annex C, Table C.1”).
• Status: unreported.

• Location: Annex C, Table C.2 (printed p. 18), the $\Delta L_w$ / $\Delta L_{\text{lin}}$ worked example.
• The print: (a) the 800 Hz reference-floor value is printed as 71,0 dB; (b) the $C_I$ line prints $L_{n,\text{sum}}=75,2527\dots =75\text{dB}$ and $C_I=75-15-63=-3\text{dB}$, feeding $\Delta L_{\text{lin}}=78-11-(63-3)=7\text{dB}$.
• The problem: two independent defects. (a) The normative Table 4 reference floor is 71,5 dB at 800 Hz, and the column itself is a clean +0,5 dB per one-third octave ramp from 67,0 dB at 100 Hz to 72,0 dB at 1000 Hz, which the printed 71,0 dB breaks by repeating the 630 Hz cell. The misprint propagates along its own row and into the table’s total, three further cells the table prints and this entry previously did not name: the $L_{n,r,0}-\Delta L$ cell at 800 Hz is printed 64,0 dB ($=71,0-7,0$) where 71,5 gives 64,5; the unfavourable deviation is printed 3,0 dB ($=64,0-61$) where the corrected cell gives 3,5; and the printed Sum 27,9 is the sum of the thirteen unfavourable deviations including that 3,0, where the corrected chain gives 28,4. None of it moves the rating: 28,4 dB is still below the 32,0 dB shift criterion, so $L_{n,w,r}=63\text{dB}$ and $\Delta L_w=15\text{dB}$ either way. (b) The printed 75,2527 dB is exactly the energy sum of the wrong column over the wrong range: the measured floor “with covering” over all sixteen bands 100 Hz to 3150 Hz. A.2.1 defines $C_I$ from the reference floor with covering (the $L_{n,r,0}-\Delta L$ column) over 100 Hz to 2500 Hz (15 bands), which gives 75,674 dB (printed chain) or 75,710 dB (corrected 800 Hz cell), both round to 76 dB, so $C_{I,r}=76-15-63=-2$ either way, giving $C_{I,\Delta }=-11-(-2)=-9$ and $\Delta L_{\text{lin}}=6\text{dB}$, not the printed −3 / −8 / 7 dB chain.
• Evidence: independent recomputation of every candidate sum and of every cell of the 800 Hz row from the printed per-band values; the printed 75,2527 reproduces to all printed digits only as the 16-band sum of the with-covering column, and every other cell of the $L_{n,r,0}-\Delta L$ and deviation columns reproduces exactly from the printed reference floor, so the 800 Hz row is the only one that does not. Verified on PDF page 24 (printed p. 18) and PDF page 13 (printed p. 7) of ISO 717-2:2020.
• Library behaviour: derives the covered reference floor from the normative Table 4 values and sums per A.2.1, pinning $\Delta L_w=15\text{dB}$ and $C_{I,\Delta }=-9$; the conformance check notes the provenance explicitly.
• Status: unreported.

• Location: Annex C: the displayed male worked example (82 kg male, $m_z=0,029\text{MPa}/({\text{m/s}}^2)$, printed p. 19) and NOTE 5 (64 kg female, $m_z=0,025\text{MPa}/({\text{m/s}}^2)$, printed p. 20).

• The print: (a) the male example is displayed as

  $$R={\left\{\sum _{i=0}^{20-1}{\left[\frac{1,62\text{MPa}(120{)}^{1/6}}{6,75\text{MPa}-0,052\text{MPa}(20+i)}\right]}^6\right\}}^{1/6}\approx 1,22$$

  and (b) NOTE 5 states $R=0,97$ for the female case.

• The problem: two independent defects. (a) The displayed male formula omits the $-S_{\text{stat},i}$ term that normative Formula (C.3) puts in the denominator, and that the same annex fixes at $S_{\text{stat}}=0,029\cdot 9,81=0,281\text{MPa}$ in the sentence that follows the where-list of Formula (C.3). Evaluated exactly as displayed the sum gives $R=1,1497$, which prints as 1,15, not the printed 1,22; restoring the missing term gives 1,2168 with the printed $S_{\text{stat}}=0,281\text{MPa}$ and 1,2177 with the exact $m_z\cdot 9,81=0,2845\text{MPa}$, i.e. the printed 1,22 either way. The printed result is therefore right and the printed formula is not. (b) Exact recomputation of Formula (C.3) with NOTE 5’s own inputs ($m_z=0,025$, age coefficient 0,039, $b=20$, $n=20$, $N=120$) gives $R=0,9621$, which rounds to 0,96; the same code reproduces the male example exactly, and the note’s $S_d=1,40\text{MPa}$ matches the exact 1,3992, so the discrepancy is confined to the last digit of the printed female $R$.

• Evidence: term-by-term recomputation of the C.3 sum under both readings of the denominator, with the male example as the discriminator: the printed 1,22 is reachable only with $-S_{\text{stat}}$, and 1,15 only without it. Verified on PDF pages 23 (printed p. 17), 24 (printed p. 18), 25 (printed p. 19) and 26 (printed p. 20) of ISO 2631-5:2018.

• Library behaviour: implements Formula (C.3) as written, with $-S_{\text{stat}}$; the male anchor pins 1,22 and the female test anchor keeps the printed 0,97 with a tolerance that documents the recomputed 0,9621.

• Status: unreported.

• Location: Principles of Sonar Performance Modelling (Springer 2010), Equation (4.6) on printed folio 127; the sea-water density quoted in Section 4.4 on printed folio 177; Equation (4.13) on printed folio 135.

• The print: Equation (4.6) gives the density of sea water as $\hat{\rho }=1027+4,3\times 10^{-7}{\hat{P}}_{\mathrm{w}}+0,75[S-35]-0,16[\hat{T}-10]-0,004[\hat{T}-10{]}^2$, attributed to Pierce (1989, p. 34), with the units fixed by Equations (4.7) to (4.10) on folio 128: pressure in pascals, temperature in degrees Celsius, density in kg/m³. Equation (4.4) on folio 127 defines that pressure as $P_{\mathrm{w}}(z)=P_{\mathrm{atm}}+{\int }_0^z\rho g\mathrm{d}\zeta$, and Equation (4.11) on folio 128 evaluates it to $98066,5\times 1,04=101989,16$ Pa at the surface. Folio 177 then states, for the ratios that scale the Bachman sediment correlations, “standard conditions involving atmospheric pressure, a temperature of 23 °C, and salinity 35” with ${\rho }_{\mathrm{w}}=1024,2$ kg/m³.

• The problem: two defects, of different kinds.

  (a) The 1024,2 of folio 177 does not follow from Equation (4.6) read with Equation (4.4). At 23 °C, salinity 35 and one atmosphere the equation gives 1024,287 9, which prints as 1024,3. The printed 1024,2 is what the equation gives with its pressure term set to zero, that is, reading $P_{\mathrm{w}}$ as a gauge pressure against the definition the same chapter states. The difference is 0,043 9 kg/m³, or 4,3 parts in a hundred thousand.

  (b) Equation (4.13), which rearranges (4.6) to estimate salinity from a measured density, prints the pressure coefficient as $4,3\times 10^{-5}$ where (4.6) has $4,3\times 10^{-7}$. Two orders of magnitude, and not a restatement of a different quantity: it is the same coefficient in the same role. Carried through at 23 °C it gives 1028,63 kg/m³ against 1024,29, an error of 0,42 %.

• Evidence: Equation (4.6) evaluated at the stated conditions with the pressure of Equation (4.11), against the value folio 177 prints; and the two printed exponents compared directly. Verified on PDF pages 157, 158, 165 and 207 (printed pp. 127, 128, 135 and 177) of the Springer 2010 edition.

• Library behaviour: implements Equation (4.6) with the absolute pressure its own Equation (4.4) defines, because a printed definition outranks a rounded quotation of a derived value three chapters later. The discrepancy is below every tolerance in this library, so nothing turns on the choice; what would have turned on it is picking a side silently. Equation (4.13) is not implemented (tests/fluids/test_water.py, conformance checks “Sea water (Ainslie 2010)”).

• Status: unreported.

• Location: Annex A.3, printed folio 13 (PDF page 17) for the first four values and printed folio 14 (PDF page 18) for the fifth.

• The print: “The following physical properties for air, valid at 23 °C, 101,325 kPa and 50 % RH, are used for the calculation (values from IEC 61094-2:2009):”, followed by $c_0=345,9$ m/s, ${\rho }_0=1,186$ kg/m³, $\kappa =1,4008$, $k_{\mathrm{a}}=0,02355$ J/(s·m·K) and, overleaf, $C_{\mathrm{P}}=938,7$ J/(kg·K).

• The problem: two of the five are not IEC 61094-2:2009 values. Table F.1 of that standard (printed folio 40) tabulates exactly five quantities at this state: $\rho$, $c_0$, $\kappa$, $\eta$ and the thermal diffusivity ${\alpha }_t=2,115317\times 10^{-5}$ m²/s. It does not tabulate the thermal conductivity or the specific heat capacity; those appear in Annex F only as the two expressions under Clause F.6, which print no values. The three Annex A.3 values that do match are precisely the three Table F.1 cells rounded to four figures ($345,86652\to 345,9$; $1,1860848\to 1,186$; $1,4007573\to 1,4008$). The two that do not match are precisely the two quantities Table F.1 does not print: evaluated at the same state, Clause F.6 gives $k_{\mathrm{a}}=0,0254341$ J/(s·m·K) and $C_{\mathrm{P}}=1013,74$ J/(kg·K), each larger than the printed pair by the same factor 1,0800.

  The common factor is not a coincidence and not a unit difference. The pair is locked to the tabulated diffusivity: $0,02355/(1,186\times 2,115317\times 10^{-5})=938,7085$, which prints as 938,7. So one of the two came from elsewhere and the other was computed back through Formula (F.5) to keep ${\alpha }_t$ right. Which one is foreign is settled by thermodynamics rather than by preference: $C_{\mathrm{P}}=938,7$ J/(kg·K) is 27,19 J/(mol·K), below the rigid-rotor diatomic floor $(7/2)R=29,10$ J/(mol·K), so it is not air at any temperature, in any unit, per mass or per mole, and the Annex F expression for $C_{\mathrm{P}}$ never falls below about 1013 J/(kg·K) anywhere from 200 K to 400 K. The conductivity 0,023 55 J/(s·m·K), by contrast, is a real conductivity of air: it is what the Annex F expression gives near −1,4 °C, outside the 15 °C to 27 °C domain Annex F prints for itself.

• Consequence for the annex’s own example: none. Formula (A.5) uses $k_{\mathrm{a}}$ and $C_{\mathrm{P}}$ only through the combination $k_{\mathrm{a}}/({\rho }_0{c}_0{C}_{\mathrm{P}})$, and the common factor cancels there, so both pairs give the printed $b=1,83\times 10^{-3}$ m and ${\kappa }^{\prime }=1,370$. The defect is invisible inside Annex A.3 and appears only when either constant is read out on its own, as a document credited with publishing it.

• Evidence: the two printed pages against IEC 61094-2:2009 Table F.1 (printed folio 40) and Clause F.6 (printed folio 39); the Clause F.6 expressions evaluated at 23 °C, 101 325 Pa and 50 % RH, which reproduce the printed ${\alpha }_t$ to $1,0\times 10^{-7}$ relative; the molar heat capacity implied by 938,7 J/(kg·K) against the diatomic floor. IEC 61094-2:2009 is not a normative reference of ISO 9053-2:2020; it appears only as Bibliography item [4]. Verified on PDF page 17 (printed p. 13) and PDF page 18 (printed p. 14) of ISO 9053-2:2020, and on PDF page 42 (printed p. 40) and PDF page 41 (printed p. 39) of BS EN 61094-2:2009.

• Library behaviour: the conformance rows that reproduce Annex A.3 pass the five values the annex prints, so they reproduce the standard rather than merely agree with it. The defaults a caller receives are the same air state computed from IEC 61094-2:2009 Annex F, which is what the annex says it is using; both land on the printed $b$ and ${\kappa }^{\prime }$ (tests/reference_data/, conformance checks “ISO 9053-2:2020 Annex A.3”).

• Status: unreported.

• Location: EN 12354-1:2000, Annex E, the wall-junction-with-flexible- interlayers block printed under Figure E.5 and numbered Formula (E.5) (printed p. 46), and ISO 12354-1:2017, E.3.4 NOTE 4. Annex E of the 2000 edition has only two numbered clauses, E.1 “Determination methods” and E.2 “Empirical data”, so “E.5” is a formula number, not a clause; an earlier revision of this entry cited it as a clause.
• The print: $K_{24}=3,7+14,1M+5,7M^2\text{dB}$; $0\le K_{24}\le -4\text{dB}$ ; $0\text{dB / octave}$, i.e. the bound on the $K_{24}$ junction term is an empty interval; the 2017 edition repeats the 2000 misprint verbatim.
• The problem: the interval is impossible as printed; the accompanying figure and the physics (the term is a reduction bounded below) indicate $-4\text{dB}\le K_{24}\le 0\text{dB}$.
• Evidence: the Figure E.5 curve family on the same page runs the $K_{24}$ branch from 0 dB down to about −4 dB over the plotted mass ratios, which is the interval read in the other order. Verified on PDF page 48 (printed p. 46) of EN 12354-1:2000 and PDF page 52 (printed p. 46) of ISO 12354-1:2017.
• Library behaviour: implements the clamp as $-4\le K_{24}\le 0$ with a misprint note in the docstring.
• Status: unreported.

• Location: Annex E, Figure E.9 / Formula (E.7) (junction of lightweight double leaf wall and homogeneous elements), the $K_{24}$ line.
• The print: $K_{24}=3,0-14,1M+5,7M^2\text{dB}$ (for $m_2/m_1>3$), under a figure whose x-axis is $m_2/m_1$.
• The problem: Annex E defines $M$ per transmission path as $M=\lg (m_{\perp ,i}^{\prime }/m_i^{\prime })$ (perpendicular element over the element carrying the path). The $K_{24}$ path 2→4 is carried by the homogeneous element ($m_2=m_4$) with the leaf ($m_1$) perpendicular, so the per-path $M$ is ${\log }_{10}(m_1/m_2)$ — but the printed $K_{24}$ line only matches its own figure’s curve when $M$ is read as the x-axis variable ${\log }_{10}(m_2/m_1)$ (e.g. −2,4 dB at $m_2/m_1=3$, −5,4 dB at 10). Read with the annex’s declared $M$, the line contradicts the figure by $28,2\cdot |{\log }_{10}(m_2/m_1)|\text{dB}$. The same edition’s other $K_{24}$ line (Figure E.5, Formula (E.5)) does follow the declared per-path $M$, so the two $K_{24}$ prints of the 2000 edition silently use different conventions. ISO 12354-1:2017 E.3.5 prints the relation consistently in the per-path convention of its Formula (E.3), $K_{24}=3,0+14,1M+5,7M^2$; the two editions agree numerically (an earlier revision of this entry read the 2017 print as a sign misprint — re-derivation against both editions’ figures shows it is a convention recast, not a defect of the 2017 text).
• Evidence: numerical evaluation of both forms against the Figure E.9 curve. Verified on PDF page 44 (printed p. 42), PDF page 48 (printed p. 46) and PDF page 50 (printed p. 48) of EN 12354-1:2000, and of PDF page 53 (printed p. 47) of ISO 12354-1:2017, whose E.3.5 prints its K24 line beside a Figure E.7 that carries no mass-ratio axis at all.
• Library behaviour: implements the per-path convention uniformly (junction_vibration_reduction, mass_ratio = $m_{\perp ,i}^{\prime }/m_i^{\prime }$ for every branch), so the E.7 double-leaf branch takes leaf-over-homogeneous ratios below 1/3 and evaluates $3,0+14,1M+5,7M^2$.
• Status: unreported.

• Location: Formula (3) and worked example E.3.
• The print: Formula (3) defines $L_{nT}^{\prime }=L_n^{\prime }-10\lg (0,16\cdot V/(A_0\cdot T_0))$, which reduces exactly to $L_n^{\prime }-10\lg (0,032\cdot V)$, i.e. a reference volume of $31,25{\text{m}}^3$. Annex E.3 states “from equation (3): $L_{nT,w}^{\prime }=L_{n,w}^{\prime }-10\lg (V/30)$”.
• The problem: the annex’s $V/30$ is a rounding of the formula’s own constant; the two differ by a constant 0,177 dB.
• Evidence: direct algebra; both variants recomputed for the E.3 case (42,959 vs 42,782 dB, both rounding to 43 in that example). Verified on PDF page 7 (printed p. 5) and PDF page 34 (printed p. 32) of EN 12354-2:2000.
• Library behaviour: implements the exact $0,032\cdot V$ form and documents the annex’s rounding.
• Status: unreported.

• Location: clause 3.1.5 “Relations between quantities”, Formula (5) (printed p. 6).
• The print: $D_{2m,n}=D_{2m,nT}-10\lg [0,16V/(T_0{A}_0)]=D_{2m,nT}-10\lg 0,32V\text{dB}$.
• The problem: the reduced form is off by a factor of ten. Six lines above it, the where-list of clause 3.1.4 defines $A_0$ as “the reference equivalent sound absorption area, in square metres, for dwellings given as 10 m²”, and the where-list of clause 3.1.3 on the preceding page defines $T_0$ as “the reference reverberation time, in seconds, for dwellings given as 0,5 s”. So $0,16/(T_0{A}_0)=0,16/5=0,032$, not 0,32. Applied as printed, the reduced form shifts every normalized façade level difference by exactly $10{\log }_{10}10=10\text{dB}$. The exact analogue in the companion part, EN 12354-2:2000 Formula (3), prints the same algebra correctly: $L_{nT}^{\prime }=L_n^{\prime }-10\lg [0,16V/(A_0{T}_0)]=L_n^{\prime }-10\lg 0,032V\text{dB}$. ISO 12354-3:2017 dropped the reduced form altogether: its Formula (5) prints only $D_{2m,n}=D_{2m,nT}-10\lg [C_{\text{sab}}V/(A_0{T}_0)]$ with $C_{\text{sab}}=0,16\text{s/m}$.
• Evidence: direct algebra with the standard’s own $A_0$ and $T_0$, and the side-by-side comparison with the correctly reduced Formula (3) of Part 2. Verified on PDF page 8 (printed p. 6) and PDF page 7 (printed p. 5) of EN 12354-3:2000, on PDF page 7 (printed p. 5) of EN 12354-2:2000 for its Formula (3), and on PDF page 12 (printed p. 6) of ISO 12354-3:2017 for the 2017 Formulae (4) and (5).
• Library behaviour: unaffected. No code path implements the reduced form: the façade model computes $D_{2m,nT}$ from Formula (13) (facade.py), and the survey method converts with the unreduced $D_{2m,n}=D_{2m}+k+10{\log }_{10}[A_0{T}_0/(0,16V)]$ of ISO 10052 Clause 3.15 (survey_insulation.py). The two standardization constants that are pre-folded elsewhere in the library are both correct: $0,032$ for the Part 2 impact form and $0,32$ for the Part 1 airborne form $D_{nT}=R^{\prime }+10{\log }_{10}(0,16V/(T_0{S}_s))$, where the denominator is an area rather than $A_0$.
• Status: unreported.

• Location: clause 4.1, Formula (13) (printed p. 9), against the worked example of Annex F (printed pp. 27-28).
• The print: Formula (13) gives $D_{2m,nT}=R^{\prime }+\Delta L_{\text{fs}}+10\lg [V/(6T_{0}S)]\text{dB}$, while the Annex F.1.3 result table prints a $D_{2m,nT}$ row that is exactly $R^{\prime }+1,5\text{dB}$ in all five octave bands and in the single-number column (25,9/23,0/26,4/36,9/39,0 against 24,4/21,5/24,9/35,4/37,5, and 29,3 against 27,8).
• The problem: on this constant the example is self-consistent and the formula is the outlier. (Two cells of the same annex table do not follow from its element rows, which is the subject of the next entry; the printed $+1,5$ dB row holds in every band regardless, so the two defects are independent.) With the example’s own inputs ($V=50{\text{m}}^3$, $S=11,3{\text{m}}^2$, $T_0=0,5\text{s}$, $\Delta L_{\text{fs}}=0$), the Sabine form gives $10{\log }_{10}[0,16\cdot 50/(0,5\cdot 11,3)]=1,5104\text{dB}$, which is the printed +1,5 dB row; Formula (13) as printed gives $10{\log }_{10}[50/(6\cdot 0,5\cdot 11,3)]=1,6877\text{dB}$. The gap is the constant: Formula (13)‘s “6” is a rounded $1/0,16=6,25$, and $10{\log }_{10}(6,25/6)=0,177\text{dB}$ is exactly the discrepancy. ISO 12354-3:2017 replaced it with an explicit Sabine constant, printing Formula (4) as $D_{2m,nT}=R^{\prime }+\Delta L_{\text{fs}}+[10\lg (C_{\text{sab}}V/(T_{0}S))]$ with $C_{\text{sab}}=0,16\text{s/m}$, which is the constant the 2000 example already used. A previous revision of this entry attributed the 1,5 dB row to the example; the attribution is the other way round.
• Evidence: evaluation of both constants against the printed Annex F rows, which agree with 0,16 to the 0,05 dB the table carries and disagree with the rounded 6 by a uniform 0,18 dB; and the 2017 recast, which adopts the example’s constant. The example’s single-number result $D_{2m,nT,w}=33\text{dB}$ is insensitive to the difference and reproduces either way. Verified on PDF pages 11 (printed p. 9), 29 (printed p. 27) and 30 (printed p. 28) of EN 12354-3:2000, and of PDF page 12 (printed p. 6) of ISO 12354-3:2017.
• Library behaviour: implements Formula (13) as printed, with the rounded 6; the test data records that the Annex F rows follow the exact 0,16 constant and sit 0,18 dB below the model.
• Status: unreported.

• Location: Annex F, table F.1.3 “Results for façade” (printed p. 28), the R' (equation 10) row.
• The print: $R^{\prime }$ = 24,4 / 21,5 / 24,9 / 35,4 / 37,5 dB at 125 / 250 / 500 / 1000 / 2000 Hz.
• The problem: the last two cells do not follow from the table’s own element rows. Formula (10), $R^{\prime }=-10{\log }_{10}\sum {\tau }_{e,i}$, applied to the four $-10{\log }_{10}{\tau }_e$ columns printed immediately above gives 24,41 / 21,50 / 24,86 / 35,78 / 37,99 dB. The first three cells reproduce to the 0,05 dB the table carries; the 1 kHz and 2 kHz cells are printed 0,4 dB and 0,5 dB low.
• Evidence: energy summation of the printed element rows band by band (1 kHz: 60,7 / 40,0 / 46,6 / 38,5 dB; 2 kHz: 66,7 / 41,0 / 43,6 / 44,5 dB). The $D_{2m,nT}$ row below is a uniform $R^{\prime }+1,5\text{dB}$ in every band including those two, so it inherits the same offset, and the single-number result $D_{2m,nT,w}=33\text{dB}$ is insensitive to it and still reproduces. Verified on PDF page 30 (printed p. 28) of EN 12354-3:2000.
• Library behaviour: the test data notes the inconsistency next to the affected anchor.
• Status: unreported.

• Location: Annex F, clause F.4.2: the symbol list of Formula (F.9), the sentence introducing the closed form, and the caption of Table F.1 (printed p. 59).
• The print: ”$L_F$ is the force level in the source room, in dB re 1 pN”; ”$L_F=10\lg 2,5f/10^{-12}$ dB re 1 pN or $L_F=10\lg 0,8f/10^{-12}$ dB re 1 pN for one-third octave bands”; and “Table F.1 – Force level $L_F$ re 1 pN for the ISO tapping machine in octave bands”, whose eight cells read 139, 142, 145, 148, 151, 154, 156 and 156 dB.
• The problem: the reference force of those levels is $10^{-6}$ N, not 1 pN. Three independent readings agree, and none of them is compatible with the printed reference. (a) The annex’s own algebra. A power level re 1 pW built from a force level and a mobility is $L_W=L_F+10\lg (F_0^{2}Y/W_0)$. Formula (D.5a) prints $L_{Ws,c}=L_{F,eq}+10\lg Y_s$ and Formula (D.9a) prints $L_{Ws,c}=L_F-5-10\lg f$, which is the same expression evaluated at the mass-like source mobility $Y_s=(2\pi fM{)}^{-1}$ of a 0,5 kg tapping hammer. Neither carries a term for $F_0^2/W_0$, so both balance only when $F_0^2/W_0=1{\text{s}}^{-1}$, that is $F_0=10^{-6}$ N; read re 1 pN each would fall 120 dB short of the level it defines. The velocity counterpart, Formula (D.10a), does print its reference term $10\lg (v_{\text{ref}}^2/W_{\text{ref}})$ and states the result cancels the $10\lg Z_s$ exactly, which it does at the $10^{-9}$ m/s the standard itself gives as the velocity-level reference in clause F.4.2. The annex is therefore explicit and correct about the velocity reference and silent about the force one. (b) The machine that produces the table. The ISO tapping machine drops 0,5 kg hammers from 40 mm at ten impacts per second, so each impact transfers a momentum of 0,443 N·s and the force is a 10 Hz impulse train every harmonic of which carries 6,26 N r.m.s. Summing the harmonics that fall inside each octave band gives 139,4 / 142,4 / 145,4 / 148,4 / 151,4 / 154,4 dB re $10^{-6}$ N from 31,5 Hz to 1 kHz, reproducing the first six cells of Table F.1 to within 0,5 dB; the 2 kHz and 4 kHz cells sit below that line, which is the roll-off the standard itself flags with “up till about 1000 Hz”. Re 1 pN the same cells would describe forces of tens of micronewtons, which no impact machine produces. (c) The companion standard. EN 15657:2018 Formula (15), which is where the structure-borne source data of Annex D comes from in the first place, writes the same force-to-power conversion “in dB re $F_0=10^{-6}$ N”, and $10^{-6}$ N is the preferred reference force of ISO 1683.
• Evidence: verified on PDF pages 61 and 62 (printed pp. 59 and 60) of BS EN 12354-5:2009, carrying clause F.4.2 with the symbol list of Formula (F.9), the closed form, the whole of Table F.1 and the symbol list of Formula (F.11) with its $10^{-9}$ m/s velocity reference; and on PDF pages 45, 48 and 50 (printed pp. 43, 46 and 48) of the same edition, carrying Formulae (D.5a), (D.9a) and (D.10a).
• Library behaviour: ships the printed cells unchanged and documents them re $10^{-6}$ N. tapping_machine_force_level returns the eight values of Table F.1, tapping_machine_force_level_estimate the closed form and tapping_machine_characteristic_power_level Formula (D.9a) as printed; test_table_f1_is_referred_to_1e_6_newton_not_1_piconewton pins the reading against the mechanics of the machine.
• Status: unreported.

• Location: Annex D, the Key of Figure D.3 (printed p. 47).
• The print: three key rows, each labelled with the same symbol: $L_{Ws,c,A}=124\text{dB}$, $L_{Ws,c,A}=119\text{dB}$ and $L_{Ws,c,A}=102\text{dB}$.
• The problem: the figure’s own caption reads “Structure-borne sound power for the ISO-tapping machine: characteristic source power, installed power on a wooden floor and installed power on a concrete floor; the A-weighted power level is also indicated”. Only the first curve is a characteristic power; the other two are installed powers and their A-weighted totals are $L_{Ws,\text{inst},A}$. The plotted curves settle the assignment: the first is flat at about 114,5 dB re 1 pW, which is the frequency-independent Formula (D.9a) result for the tapping machine, while the other two rise with frequency and lie below it, the concrete floor lowest, as $L_{Ws,c}-D_{C,i}$ requires.
• Evidence: verified on PDF page 49 (printed p. 47) of BS EN 12354-5:2009, the page carrying Figure D.3 with its Key and its caption.
• Library behaviour: none required; no value is read from Figure D.3. test_formula_d9a_is_flat_at_about_115_db_per_third_octave pins the flat characteristic curve that the first key row belongs to.
• Status: unreported.

• Location: the input-data block below Table L.3 (printed p. 81) and the identical block below Table G.3 (printed p. 38), which lists the perimeter absorption sum $\sum l_k{\alpha }_k$ of Formula (C.1) for the worked example.
• The print: one value per element type: separating floor 2,364 m ($S=20{\text{m}}^2$), external wall 2,375 m ($S=11{\text{m}}^2$), internal wall 1,840 m ($S=13,75{\text{m}}^2$).
• The problem: Formula (C.1) needs one sum per element, and the example has five elements with three different areas. Only two of the three printed values reproduce the columns they are supposed to drive: 2,375 m with $S=11{\text{m}}^2$ gives external wall 1 exactly, and 1,840 m with $S=13,75{\text{m}}^2$ gives internal wall 2 exactly. The separating floor’s printed 2,364 m does not reproduce its own column at any band (0,074 9 against the printed 0,083 1 at 50 Hz, 0,026 4 against 0,029 0 at 500 Hz); 2,659 m does, at every band. The two elements with no printed value need 2,548 m (external wall 2, $S=13,75{\text{m}}^2$) and 1,636 m (internal wall 1, $S=11{\text{m}}^2$).
• Evidence: all five sums re-derived from Formula (C.4), ${\alpha }_k={\sum }_j\sqrt{f_{c,j}/f_{\text{ref}}}10^{-K_{ij}/10}$, over the example’s own junction geometry with the unrounded Annex E indices: 2,659 / 2,375 / 2,548 / 1,636 / 1,839 m. The derivation returns the two printed values that are self-consistent with their own columns (2,375 m, and 1,839 m against the printed 1,840 m) and supplies the three that are missing or wrong, and every ${\eta }_{\text{tot,situ}}$ column of Table L.3 / G.3 then reproduces to $5\cdot 10^{-5}$. The printed values applied to the wrong element of the same type miss by far more than that rounding: 2,375 m on external wall 2 gives 0,108 5 against the printed 0,114 9 at 50 Hz, and 1,840 m on internal wall 1 gives 0,085 0 against 0,077 0.
• Library behaviour: in_situ_total_loss_factor takes $\sum l_k{\alpha }_k$ as an input and perimeter_absorption_coefficient implements Formula (C.4); the Annex L fixture derives all five sums that way rather than using the printed block, and says so (tests/building/prediction/test_detailed_model.py).
• Status: unreported.

• Location: the same input-data block, external-wall line.
• The print: ${\eta }_{\text{int}}=0,013$ for the 365 mm autoclaved aerated concrete external walls.
• The problem: the example’s own element specification, and Annex B Table B.3 for autoclaved aerated concrete, give 0,012 5. Only 0,012 5 reproduces the tabulated ${\eta }_{\text{tot,situ}}$: at 500 Hz Formula (C.1) gives $0,0125+0,00141+0,03457=0,0485$, the printed value, where 0,013 would give 0,049 0.
• Evidence: term-by-term recomputation of Formula (C.1) for both external walls at every band with each candidate ${\eta }_{\text{int}}$.
• Library behaviour: the Annex L fixture uses 0,012 5.
• Status: unreported.

• Location: Annex L, Table L.4 (printed p. 82), the right-hand block headed “Transmission path 2d”.
• The print: the block gives ${\alpha }_{i,\text{situ}}$ = 6,3 to 14,1, $D_{v,ij,\text{situ}}$ = 11,0 to 13,6 and $R_{ij}$ = 43,9 to 84,6 dB.
• The problem: those are the numbers of path 4d (internal wall 2 to the separating floor), not of path 2d (external wall 2). Table L.1 of the same annex prints the whole $R_{4d}$ column, 43,9 to 84,6 dB, and the block’s $R_{ij}$ column is that column cell for cell. What settles it band by band is the other two columns, which cannot be confused: external wall 2 has ${\alpha }_{i,\text{situ}}=10,3\text{m}$ at 50 Hz ($S=13,75{\text{m}}^2$, ${\eta }_{\text{tot}}=0,1149$) while internal wall 2 has 6,3 m (${\eta }_{\text{tot}}=0,0703$), the printed value; and $D_{v,ij,\text{situ}}$ follows the floor-to-internal-wall $K_{ij}$ of 8,8 dB, which gives 11,0 to 13,6 dB, not the floor-to-external-wall 6,4 dB, which gives 9,6 to 11,9 dB.
• Evidence: independent recomputation of Formulae (10), (11) and (15) for both candidate paths at every band. Path 4d reproduces all three columns of the block, ${\alpha }_{i,\text{situ}}$ to 0,05 m and $D_{v,ij,\text{situ}}$ and $R_{ij}$ to 0,05 dB, which is the printed resolution. Path 2d departs from the block’s $R_{ij}$ column by 0,1 dB to 7,0 dB depending on the band, and comes closest between 100 Hz and 160 Hz (0,5 / 0,5 / 0,1 dB), so $R_{ij}$ alone does not identify the path over those bands; ${\alpha }_{i,\text{situ}}$ (10,3 against 6,3 m at 50 Hz) and $D_{v,ij,\text{situ}}$ (1,4 dB to 1,7 dB apart in every band) do.
• Library behaviour: the test that asserts the block builds it as path 4d and names the mislabelling.
• Status: unreported.

• Location: Annex L, Table L.1 (printed p. 79), the $R_w$ row and the sentence below it, and the corresponding $L_{n,w}$ row of ISO 12354-2:2017 Table G.1.
• The print: the $R_w$ row gives one decimal for every path (75,1 / 84,5 / 70,6 / … and 57,8 in the total column) while the sentence immediately below states $R_w^{\prime }(C;C_{\text{tr}})=57,9(-2;-8)\text{dB}$.
• The problem: ISO 717-1 rates by shifting the reference curve in 1 dB steps, so a weighted rating is an integer; the printed one-decimal values are the reference curve shifted continuously until the sum of unfavourable deviations equals exactly 32,0 dB. The airborne $R_w$ row of Table L.1 truncates that continuous value to one decimal while the sentence below it rounds, which is why the same quantity appears twice as 57,8 and 57,9; the impact $L_{n,w}$ row of Table G.1 rounds instead (29,58 prints as 29,6 and 40,98 as 41,0), so the truncation is a property of the airborne row only. The spectrum adaptation terms inherit the offset: with the ISO 717-1 rating of 57 dB they are $C=-1$ and $C_{\text{tr}}=-7$, and the printed (−2 ; −8) is exactly the pair shifted by the same 0,86 dB.
• Evidence: a continuous-shift solve of the ISO 717-1 reference curve against the printed per-band spectra reproduces every printed value in both rows ($R_{Dd}$ 75,12 against 75,1; $R_{D1}$ 84,54 against 84,5; $R_{11}$ 70,66 against 70,6; the total 57,86 against 57,8 / 57,9; on the impact side $L_{n,Df1}$ 29,58 against 29,6 and the total 40,98 against 41,0), whereas the ISO 717-1 1 dB-step ratings of the same spectra are 75, 84, 70 and 57 dB. Verified on PDF page 85 (printed p. 79) of ISO 12354-1:2017.
• Library behaviour: weighted_rating / weighted_impact_rating implement ISO 717-1/-2 as written, so the detailed model returns $R_w^{\prime }=57\text{dB}$ and $L_{n,w}^{\prime }=41\text{dB}$ ($C_I=2$) for the example; the test pins those and documents the printed values.
• Status: unreported.

• Location: Annex G, Table G.1 (printed p. 36), the four $L_{n,Df}$ columns, 50 Hz, 63 Hz and 80 Hz rows.
• The print: $L_{n,Df1}$ = 47,3 / 44,9 / 46,2 dB.
• The problem: Table G.4 of the same annex prints the same path Df for external wall 1, from the same inputs, as 47,8 / 45,9 / 47,0 dB. The two tables cannot both be right, and from 100 Hz upwards they agree exactly.
• Evidence: Formula (12) evaluated from the annex’s own Table G.3 columns ($L_{n,\text{situ}}$, $R_{\text{situ}}$) and the Table G.4 $D_{v,ij,\text{situ}}$ and $\Delta L_{\text{situ}}$ columns gives 47,80 / 45,85 / 46,95 dB, reproducing the printed 47,8 / 45,9 / 47,0 of Table G.4 to 0,05 dB and Table G.1 only from 100 Hz upwards. Carrying the same recomputation through the whole chain puts external wall 2 low by 0,5 dB to 1,0 dB over the same three bands and the two internal walls low by up to 0,5 dB at 50 Hz and 63 Hz (their 80 Hz cells agree). From 100 Hz upwards no flanking column deviates by more than 0,15 dB. Correcting the affected cells raises the printed total $L_n^{\prime }$ only slightly: 58,6 to 58,7 dB at 50 Hz, 57,0 to 57,2 dB at 63 Hz, 55,9 to 56,1 dB at 80 Hz.
• Library behaviour: the test asserts Table G.4 in full, the Table G.1 direct column over the whole range, and the Table G.1 flanking columns from 100 Hz upwards, naming the disagreement.
• Status: unreported.

• Location: Annex G, Table G.8 (printed p. 40), the internal wall to external wall rigid T junction.
• The print: row “Int. wall 1/2 - Ext. wall 1/2” gives $K_{ij}=6,6\text{dB}$; the row below it, “Ext. wall 1/2 - Ext. wall 1/2”, gives $m_i^{\prime }=2,19{\text{kg/m}}^2$.
• The problem: two independent misprints. The rigid-T corner branch $K_{12}=5,7+5,7M^2$ with $M={\log }_{10}(360/219)=0,2156$ gives 5,97, i.e. 6,0, and ISO 12354-1:2017 Table L.8 prints 6,0 for the identical junction of the identical example. And the external wall’s mass per unit area is $219,0{\text{kg/m}}^2$ throughout the example, not 2,19 (a factor 100).
• Evidence: Annex E evaluation of the corner branch; the same table’s own other rows and the whole of ISO 12354-1 Annex L use $219,0{\text{kg/m}}^2$. Verified on PDF page 46 (printed p. 40) of ISO 12354-2:2017, whose Table G.8 mass columns are headed m'i and m'orthogonal, and PDF page 89 (printed p. 83) of ISO 12354-1:2017.
• Library behaviour: uses 6,0 dB and $219,0{\text{kg/m}}^2$.
• Status: unreported.

• Location: Annex G, Table G.6 (printed p. 40), internal wall to separating floor rigid cross junction.
• The print: a row labelled “Ext. wall 1/2 – Int. wall 1/2” with m'i = 360,0, m'orthogonal = 484,0 and $K_{ij}=11,0\text{dB}$.
• The problem: Table G.6 describes the internal wall to separating floor cross junction; no external wall meets it. The masses and the value are those of the in-line internal-wall path, and ISO 12354-1:2017 Table L.6 prints the same row correctly as “Int. wall 1/2 - Int. wall 1/2”.
• Evidence: the rigid-cross through branch $8,7+17,1M+5,7M^2$ with $M={\log }_{10}(484/360)$ gives 10,99, the printed 11,0, for the internal wall. Verified on PDF page 46 (printed p. 40) of ISO 12354-2:2017 and PDF page 89 (printed p. 83) of ISO 12354-1:2017.
• Library behaviour: treats the row as the internal-wall in-line path.
• Status: unreported.

• Location: the simplified-model input table of both parts, fourth row: Table L.10 (printed p. 84) and Table G.10 (printed p. 41).
• The print: ISO 12354-1 prints “Internal wall 4 (F = f = 4)”; ISO 12354-2 prints “Internal wall 4 (f4)”: the two parts label the row differently, and an earlier revision of this entry quoted the Part 1 form for both.
• The problem: the example has two internal walls; the element indexed $F=f=4$ is internal wall 2 ($5,00\text{m}\times 2,75\text{m}$, $S=13,75{\text{m}}^2$), as the detailed-model tables of the same annexes label it.
• Evidence: the row’s own $S=13,75{\text{m}}^2$ and $l_{ij}=5,0\text{m}$ match internal wall 2 of Table L.1 / G.1. Verified on PDF page 90 (printed p. 84) of ISO 12354-1:2017 and of PDF page 47 (printed p. 41) of ISO 12354-2:2017, with the detailed-model column labels read on PDF page 85 (printed p. 79) of ISO 12354-1:2017 and of PDF page 42 (printed p. 36) of ISO 12354-2:2017.
• Library behaviour: none needed; the numbers are unaffected.
• Status: unreported.

• Location: Annex D, Table D.1 (printed p. 39), which reads the weighted sound reduction index improvement of an interior lining off its resonance frequency.

• The print: the last two rows are “630 to 1 600 -> -10” and “1 600 <= f0 <= 5 000 -> -5”.

• The problem: 1 600 Hz belongs to both rows, with different values, and Clause D.2.2 requires $f_0$ to be “rounded to the centre frequency of the one-third-octave band in which fo falls”, so 1 600 Hz is a value the table is actually read at rather than an unreachable edge. Because the rounding is mandatory, the ambiguity is not a single point: every raw resonance frequency in the 1 600 Hz band, that is from 1 412,5 Hz to 1 778,3 Hz (ISO 266 band edges), lands on it. Every other boundary in the table is a distinct band centre (200, 250, 315, 400, 500 Hz), and no other pair of rows overlaps.

• Evidence: the printed table itself, on PDF page 45 (printed p. 39) of ISO 12354-1:2017: the two rows are separately ruled and share the endpoint verbatim, “630 to 1 600” and “1 600 <= f0 <= 5 000”. Neither row can be discarded, because 630 Hz to 1 250 Hz has no other entry and 2 000 Hz to 5 000 Hz has none either. The predecessor edition gives the earlier, unambiguous reading: EN 12354-1:2000 Table D.3, verified on PDF page 43 (printed p. 41) of that edition, prints the same pair of rows as “630 - 1 600 -> -10” and ”> 1 600 -> -5”, strictly greater, so in 2000 exactly 1 600 Hz took -10 dB with nothing to decide. The 2017 rewrite replaced ”> 1 600” with “1 600 <= f0 <= 5 000” while leaving “630 to 1 600” untouched, which is what creates the overlap; what the rewrite intended at the shared endpoint the text does not say.

• Library behaviour: weighted_lining_improvement returns the more conservative -10 dB at exactly 1 600 Hz and -5 dB above it, the 2000 reading, with the ambiguity named in the docstring and pinned in tests/building/prediction/test_resilient_layers.py.

• Status: unreported.

• Related, not an erratum: NOTE 1 of the same table sets a floor of 0 dB on the 30 Hz to 160 Hz branch $74,4-20{\log }_{10}(f_0)-R_w/2$. Inside the validity box Clause D.2.2 states for the table ($30\text{Hz}\le f_0\le 160\text{Hz}$, $20\text{dB}\le R_w\le 60\text{dB}$) the branch never reaches it: its minimum is $74,4-20{\log }_{10}(160)-60/2=0,32\text{dB}$. The floor is therefore inactive for every input the table is stated for, but it was not always: the 2000 edition tabulated the low branch as four discrete rows ending in “160 -> 28 - Rw/2”, whose minimum is $28-60/2=-2\text{dB}$, so NOTE 1 was operative there. The 2017 continuous fit sits 2,3 dB above it at that corner and left the note vestigial. The library keeps the floor because the note is still printed.

• Location: Clause 3.9, Formula (8) (printed p. 3), the intensity element normalized level difference for N small building elements measured together. The print read here is BS EN ISO 15186-1:2003, the identical-text British adoption; the entry previously carried the heading ":2000", the year of the ISO edition the library’s docstrings cite, which is not the copy that was read.
• The print: $D_{I,n,e}=L_{p1}-6-(L_{In}+10\lg (S_m/A_0)+10\lg (N))$, i.e. the $10\lg N$ term is subtracted.
• The problem: the subtracted sign cannot be derived. Measuring $N$ identical units within one measurement surface raises the transmitted power (and hence $L_{In}+10{\log }_{10}{S}_m$) by $10{\log }_{10}N$, so recovering the per-unit $D_{I,n,e}$ requires adding $10{\log }_{10}N$. The pressure-based equivalent, ISO 10140-2:2010 Formula (6), prints exactly that correction ($D_{n,e}=L_1-L_2+10{\log }_{10}(n{A}_0/A)$), and ISO 15186-2:2010 Formula (12) prints Formula (8) without any $N$ term (the $N=1$ case, with which both signs agree). As printed, installing more units would lower the per-unit rating by $20{\log }_{10}N$ relative to the derivable value.
• Evidence: derivation from the diffuse-field receiving-room relation $L_2=L_W+10{\log }_{10}(4/A)$ against ISO 10140-2:2010 Formula (6); cross-check against ISO 15186-2:2010 Formula (12) and Hopkins, Sound Insulation (2007), Eq. 3.45. Verified on PDF page 11 (printed p. 3) of BS EN ISO 15186-1:2003, with the cross-check read on PDF page 11 (printed p. 11) of ISO 10140-2:2010. Part 3 of the same series settles it in the series’ own words: ISO 15186-3:2002, Clause 3.9, Formula (8) states the same quantity as $D_{I,n,e}=L_{pS}-9-[L_{In}-10\lg (A_0/S_m)-10\lg N]$, whose bracket carries $10\lg N$ with the opposite outer sign, i.e. the $+10{\log }_{10}N$ derived here. Read on PDF page 10 (printed p. 4) of BS EN ISO 15186-3:2010.
• Library behaviour: implements the derivable per-unit form (intensity_element_normalized_difference, $+10{\log }_{10}N$) and emits a warning whenever $n>1$, where the result deviates from the print.
• Status: unreported.

• Location: Annex A (normative), A.2 and Table A.1, “Calculated sound reduction index (at 1 013 hPa and 23 °C)”, the qualification example a laboratory checks its facility against. The print read here is BS EN ISO 15186-3:2010, the identical-text British adoption of ISO 15186-3:2002, PDF page 18 (printed p. 12).

• The print: two columns of six one-third-octave values, 50 Hz to 160 Hz. The plaster-board column is headed “10 kg/m²” over a “Test opening 10 m²” and reads 10,7 / 11,9 / 13,4 / 14,8 / 16,3 / 17,9. The steel column is headed “17 kg/m²” over a “Test opening 1,25 m × 1,50 m” and reads 21,3 / 21,2 / 21,7 / 22,7 / 23,8 / 25,1. A.2 also states that “the dimensions of the free part of the panel are 1,162 m × 1,412 m”.

• The problem: no reading of the inputs printed beside the steel column reproduces it. With the test opening (1,875 m²) and the stated mass, the six computed values fall 1,27 dB to 0,72 dB below the printed ones. The 0,55 dB spread between those two ends rules out any surface mass at that area, because a mass error shifts $R_0=20\lg (\pi fm/\rho c)$ by the same amount in every band. With the free part of the panel (1,640744 m²) the residual is nearly flat, mean 0,562 dB, but it still spreads 0,102 dB end to end, which is the whole width of the printed decimal, so it is not the constant offset a wrong mass alone would leave either.

  No single input closes it to the 0,05 dB that one-decimal printing allows. The best surface mass alone, over the free part, is 18,13 kg/m² and leaves 0,051 dB; the best static pressure alone is 950 hPa and leaves 0,051 dB; the best temperature alone, over the test opening, is 63 °C and leaves 0,052 dB. The last two contradict the caption, which fixes the climate at 1 013 hPa and 23 °C, and the plaster-board column reproduces at exactly that climate, so the two columns cannot be read at different ones.

  The only reading that does reproduce all six values moves two inputs at once: an area of about 1,654 m², near the free part but not equal to it, together with a surface mass of about 18,16 kg/m². That mass is not available to the specimen described. Solid steel 2,2 mm thick is 16,9 kg/m² to 17,3 kg/m², and the leaf is a steel/resin/steel sandwich, so its surface mass is necessarily below that. The plaster-board column of the same table, from the same formulas at the same climate, reproduces all six of its values to within 0,050 dB.

• Evidence: Formulas (A.1) to (A.5) evaluated at the stated 1 013 hPa and 23 °C, read on PDF pages 17 and 18 (printed pp. 11 and 12) of BS EN ISO 15186-3:2010. ISO 140-3:1995, C.2.4, which A.2 cites as the source of the specimen, describes the 2,2 mm steel/resin/steel leaf but states no surface mass, so the 17 kg/m² is not carried over from there. No corrigendum to Annex A was found.

• Library behaviour: limp_panel_reduction_index implements Formulas (A.1) to (A.5) as printed. The conformance suite anchors them on the plaster-board column alone; the steel column is deliberately not used as an oracle.

• Status: unreported.

• Location: Clause 8.1.1, Formula (20), the thin-plate critical frequency used by the test-facility flanking criterion of Formula (19).
• The print: $f_c=c_0^2/(1,8c_L\cdot h\cdot \pi )$.
• The problem: the constant 1,8 is itself the rounded $2\pi /\sqrt{12}\approx 1,814$ of the thin-plate dispersion relation, so the extra $\pi$ double-counts it and would misplace $f_c$ by a factor $\pi$ (e.g. a 100 mm concrete element with $c_L=3500\text{m/s}$: 187 Hz without the $\pi$, 59 Hz with it, far from any measured coincidence dip).
• Evidence: derivation from the thin-plate dispersion relation (Hopkins, Sound Insulation (2007), Eq. 2.201, $f_c=c_0^2/(1,8c_{L}h)$); ISO 12354-1:2017 prints the same $\pi$-free form in its symbol definitions ($f_c=c_0^2/(1,8c_{L}t)$).
• Library behaviour: implements the $\pi$-free form (phonometry.building.measurement.flanking_transmission.critical_frequency), with a misprint note in the docstring.
• Status: corrected upstream — ISO 10848-1:2017 (second edition) prints the $\pi$-free form in its Formula (5), $f_c=c_0^2/(1,8h{c}_L)$, confirming the 2006 print as a misprint. No report is needed. The entry is retained because the library cites the 2006 edition, whose print carries the defect; the 2017 edition stands as the confirmation.

• Location: Clause 7.1, the sentence introducing Formula (14) (printed p. 14) and Formula (14) itself (printed p. 15), the structural power level injected into the reception plate.
• The print: the sentence reads “a partir del nivel de velocidad promediado espacialmente de la placa $L_v$, de la masa por unidad de superficie $m$, del área de la placa $S$ y del factor de pérdida $\eta$, utilizando $f_0=1$ Hz, $m_0=1$ kg y $S_0=1$ m² como referencias”, above $L_{Ws}=\left(10\lg \left(\frac{2\pi fm\eta S}{f_0\cdot m_0\cdot S_0}\right)\right)\text{dB}+L_v-60\text{dB}$.
• The problem: the same sentence defines $m$ as a mass per unit area, in kg/m², and its reference $m_0$ as 1 kg. With $m$ in kg/m² and $S$ in m², the group $2\pi f\eta mS/(f_0{m}_0{S}_0)$ is dimensionless only if $m_0$ is 1 kg/m²; as printed it carries a leftover m⁻². The closing constant confirms the intended reading: $10\lg (f_0{m}_0{S}_0{v}_0^2/P_0)=-60$ dB with $v_0=10^{-9}$ m/s and $P_0=1$ pW closes in watts only when $f_0{m}_0{S}_0$ has the units of an area density times an area times a frequency. The numeric result is unaffected, because $10\lg (1)=0$ whichever unit is attached, which is why the slip survives a worked example.
• Evidence: dimensional analysis of Formula (14) against the definition of $m$ in the sentence above it, and against the $-60$ dB constant it closes on; the sentence and the formula were read as images, not from extracted text. Verified on PDF page 14 (printed p. 14) and PDF page 15 (printed p. 15) of UNE-EN 15657:2018. Only the Spanish-language adoption was read, so this entry does not establish whether the English EN 15657:2018 print carries the same reference.
• Library behaviour: no change required. characteristic_reception_plate_power takes mass_per_area in kg/m² and reproduces the standard’s own worked values, so the intended reading is the implemented one; the guide and the docstring keep the printed reference and name this entry beside it.
• Status: unreported.

• Location: Table 4 (in-situ uncertainties per band).
• The print: the 2020 edition’s table omits the 500 Hz row that the 2014 edition prints (situation B 1,2 dB / situation C 0,8 dB).
• The problem: likely an editorial omission; the surrounding rows are unchanged between editions and the text does not mention removing the band.
• Evidence: side-by-side comparison of the 2014 and 2020 prints.
• Library behaviour: follows the 2020 print as published, with the omission documented in the module.
• Status: unreported.

• Location: Clause 8 “Reporting uncertainties” (printed pp. 5-6), the where-list under Formula (10), against the worked Tables 4 and 5 (printed p. 7). An earlier revision of this entry called the clause “expression of results”, which is not its printed title.
• The print: the where-list defines $u$ as “the standard uncertainty determined in accordance with Clause 5, Clause 6 or Clause 7 rounded to two decimal digits for absorption coefficients or one decimal digit for all other quantities”, and Formula (10) then forms $U=k\cdot u$.
• The problem: the document’s own Tables 4 and 5 only reproduce when $U$ is computed from the unrounded $u$ and rounded last. Neither table prints a $u$ column at all (each has only the coefficient ${\alpha }_s$ or ${\alpha }_p$ and $\pm U$ with $k=2$), so the printed $U$ values are the whole of the evidence, and 11 of the 25 are unreachable under the literal clause wording.
• Evidence: recomputation of all 25 entries (Table 4: 20 rows, Table 5: 5 rows) from Formula (1) with the Table 1 constants and from Formula (4) with the Table 2 constants, under both conventions. Round-last reproduces 25 of 25; round-first misses 11 of 25 (63, 125, 160, 200, 250, 1250, 1600, 2000, 3150 and 4000 Hz of Table 4, and 250 Hz of Table 5). An earlier revision of this entry quoted the count as “10 of 20”, which is neither the right numerator nor the right number of entries. Verified on PDF pages 9 (printed p. 3), 10 (printed p. 4), 11 (printed p. 5) and 13 (printed p. 7) of ISO 12999-2:2020.
• Library behaviour: rounds last, matching the tables; the convention is documented and tested.
• Status: unreported.

• Location: clause 8, Table 5 “Example for the practical sound absorption coefficient, αp, and its expanded uncertainty under reproducibility conditions” (printed p. 7).
• The print: the frequency column of Table 5 is headed “One-third octave midband frequency / Hz” and its rows are 250, 500, 1 000, 2 000 and 4 000 Hz.
• The problem: those five frequencies are the octave-band series of ISO 11654, which is what the practical sound absorption coefficient ${\alpha }_p$ is defined over; they are not a one-third-octave series, and no one-third octave band is missing between them. The document contradicts itself on the same quantity two pages earlier: Table 2, which supplies the $m$ and $n$ constants of Formula (4) for exactly these five frequencies, is headed “Octave midband frequency”. The same header text stands over Table 4 on the same page, where it is correct: that table carries a genuine one-third-octave series, 63 Hz to 5 000 Hz in 20 rows.
• Evidence: the five tabulated frequencies themselves, and the “Octave midband frequency” header of Table 2 for the same ${\alpha }_p$ constants. Verified on PDF page 13 (printed p. 7) and PDF page 11 (printed p. 5) of ISO 12999-2:2020.
• Library behaviour: _TABLE2 in uncertainty.py is keyed by octave midband frequency, following Table 2 and the ISO 11654 definition of ${\alpha }_p$ rather than the Table 5 header.
• Status: unreported.

• Location: Table 4 (reverberation-index estimator), volume-range header.
• The print: the header reads “60 ≤ V < 150” while the body text says the method applies to rooms “up to 150 m³”.
• The problem: the boundary $V=150{\text{m}}^3$ is included by the text and excluded by the header.
• Evidence: direct comparison of header and clause text.
• Library behaviour: accepts $V=150$ (follows the text), with the ambiguity noted.
• Status: unreported.

• Location: Clause 6 “General”, the paragraph on the reverberation time (printed p. 6).
• The print: “For the reverberation time, the low-frequency procedure shall be used for the 50 Hz, 63 Hz, and 80 Hz one-third octave bands in the source and/or receiving room when its volume is smaller than 25 m³ (calculated to the nearest cubic metre).”
• The problem: ISO 16283-1 measures no source-room reverberation time, so there is nothing in the source room for a reverberation-time procedure to be used on. The first paragraph of the same clause, five paragraphs and a NOTE earlier, lists the required measurements as “the sound pressure levels in both rooms with the source(s) operating, the background noise in the receiving room … and the reverberation times in the receiving room”. Clause 10, which is where the reverberation-time procedures are actually specified, says the same thing four times over: its heading is “Reverberation time in the receiving room (default and low-frequency procedure)”, its Clause 10.1 scopes the whole clause to “the receiving room”, its Clause 10.3 branches on whether “the receiving room has a volume larger than or equal to 25 m³”, and its Clause 10.4 applies the low-frequency procedure “when the receiving room volume is smaller than 25 m³”. The phrase is correct two paragraphs above, one of them the NOTE, where it belongs: the sound pressure level really is measured in both rooms and its low-frequency procedure really does apply to either. It was carried down into the reverberation-time sentence, where only one room exists. The other two parts print the same sentence with one room: ISO 16283-2:2020 Clause 6 and ISO 16283-3:2016 Clause 6 both read “in the receiving room when its volume is smaller than 25 m³”, so Part 1 is the outlier of the three.
• Evidence: the sentence on PDF page 12 (printed p. 6) of ISO 16283-1:2014, identical on PDF page 14 (printed p. 6) of BS EN ISO 16283-1:2014; Clause 10 and its subclauses on PDF pages 23 and 24 (printed pp. 17 and 18) of the same document; and the one-room version of the sentence on PDF page 13 (printed p. 7) of ISO 16283-2:2020 and PDF page 16 (printed p. 10) of ISO 16283-3:2016.
• Library behaviour: the 63 Hz octave substitution is a receiving-room operation in every part, following Clause 10; a source-room procedure that carries a 63 Hz octave reverberation time is refused, and a source-room call takes no reverberation times at all. The corner procedure for the level, which is the paragraph the phrase belongs to, does admit both rooms in ISO 16283-1 and the airborne entry point offers both.
• Status: unreported.

• Location: Clause 8.3 “Microphone positions”, last paragraph (printed p. 15).
• The print: “For the 50 Hz, 63 Hz and 80 Hz one-third octave bands, calculate the low-frequency energy-average sound pressure level for the source and/or receiving room according to 8.5.”
• The problem: an impact measurement has no source-room sound pressure level to calculate. Every other statement of the same procedure in the same part names one room: Clause 6 introduces it as used “in the receiving room when its volume is smaller than 25 m³” (printed p. 6), Clause 8.1 repeats “in the receiving room” (printed p. 14), Clause 8.5 builds $L_{\text{i,Corner}}$ from corners of the receiving room (printed p. 16), and Formulae (1) and (3), which the same sentence sends the reader to, are written in $L_{\text{i}}$, the energy-average impact sound pressure level in the receiving room. The phrase is correct where it comes from: ISO 16283-1 Clause 8.3 says “for the source and/or receiving room” of an airborne measurement, where both rooms do carry a level. It was carried across into the impact part and survived the revision unchanged.
• Evidence: the sentence on PDF page 21 (printed p. 15) of ISO 16283-2:2020 beside the same sentence on PDF page 23 (printed p. 15) of the ISO/DIS 16283-2 text circulated as BSI DPC 13/30269186 DC, and the airborne original on PDF page 21 (printed p. 15) of ISO 16283-1:2014.
• Library behaviour: the impact entry point takes a receiving-room low-frequency procedure and nothing else, following Clause 6, 8.1 and 8.5; only the airborne entry point, where ISO 16283-1 Clause 8.1 really does admit both rooms, offers a source-room one.
• Status: unreported.

• Location: Clause 10.3 “Default procedure” for the reverberation time (printed p. 18).
• The print: “for all one-third octave bands between 50 Hz and 5 000 Hz when the receiving room has a volume larger than 25 m³ (calculated to the nearest cubic metre) and between 100 Hz and 5 000 Hz when the receiving room has a volume smaller than 25 m³ (calculated to the nearest cubic metre)”.
• The problem: a receiving room that rounds to exactly 25 m³ falls in neither branch, so the clause states no frequency range for it. The other two parts print “larger than or equal to 25 m³” in the otherwise identical sentence, which closes the boundary. The intended reading is not in doubt: the trigger of Clause 8.1 and Clause 10.4 is “smaller than 25 m³” in all three parts, so 25 m³ belongs to the larger branch and takes the full 50 Hz to 5 000 Hz default range.
• Evidence: PDF page 24 (printed p. 18) of ISO 16283-2:2020, against PDF page 24 (printed p. 18) of ISO 16283-1:2014 and PDF page 24 (printed p. 18) of ISO 16283-3:2016, both of which carry the “or equal to”. The gap is not a 2020 slip and not an artefact of a draft: the ISO/DIS text on PDF page 26 (printed p. 18) of BSI DPC 13/30269186 DC already read the same way, and so does the published previous edition, whose Clause 10.3 on PDF page 25 (printed p. 25) of UNE-EN ISO 16283-2:2016, the Spanish translation of ISO 16283-2:2015, reads “un volumen superior a 25 m³” with no “o igual a”. The wording has stood unchanged across two editions and one revision.
• Library behaviour: the trigger predicate is the strict “smaller than 25 m³” the three parts share, so a room of exactly 25 m³ takes the default procedure in every part and no gap exists.
• Status: unreported.

• Location: Clause 5 (representative expanded uncertainties), printed p. 4.
• The print: “5 dB for the low frequency (10 Hz to 100 Hz) bands, 3 dB for the mid frequency (125 Hz to 16 000 Hz) bands, and 4 dB for the high frequency (>20 000 Hz) bands”.
• The problem: the 20 kHz one-third-octave band itself is left unassigned: the mid range ends at 16 kHz inclusive and the high range starts strictly above 20 kHz. ISO 17208-1:2016, from which clause 5 says the values are taken, prints the same three ranges with “≥20 000 Hz”, which closes the gap; Part 2 degraded the $\ge$ to a $>$. The 20 kHz band is not a corner case for this document: ISO 17208-1 Table 1 requires the measurement to cover “20 000 Hz (minimum)” as its upper one-third-octave band. An earlier revision of this entry said “nothing covers 16 kHz to 20 kHz inclusive”, which is wrong at the lower end: 16 kHz is covered.
• Evidence: the two clauses side by side. Verified on PDF page 10 (printed p. 4) of ISO 17208-2:2019 and PDF page 22 (printed p. 16) of ISO 17208-1:2016.
• Library behaviour: applies the conservative 4 dB high-band value from the 20 kHz band upwards, following Part 1, with the gap documented.
• Status: unreported.

• Location: clause 4.1.1 “frequency range of interest”, NOTE 2 (printed p. 2). An earlier revision of this entry cited clause 4.1.2, which is the definition of “ITT equipment” and says nothing about frequency.
• The print: “From viewpoint of test implementation by using FFT analyser, the frequency range of discrete tones are between 89,1 Hz and 11 220 Hz inclusive, referred to the discrete tone frequency range of interest.”
• The problem: every formula and table of the standard works to 11 200 Hz: the Table 2 and Table 3 band-edge fits are stated for $11200\ge f_t>1600$, and clauses 10, 12.3 and 12.4 permit FFT data with $f_1<89,1\text{Hz}$ and $f_2>11200\text{Hz}$. The two numbers are the same quantity to different precision rather than a typographical error: $10000\cdot 2^{1/6}=11224,6\text{Hz}$ is the upper edge of the 10 kHz one-third-octave band that closes the range of interest, which rounds to 11 220 Hz at four significant figures and to 11 200 Hz at three. An earlier revision of this entry called it a typo and added that “no other clause mentions 11 220 Hz”; the last x-axis tick of Figure 6 (printed p. 20) is labelled 11220. What clause 4.1 does carry is a structural defect: 4.1.2 “ITT equipment” repeats 4.1.1’s NOTE 1 verbatim (“This range was selected to be identical to that of ECMA-74:2022, 3.1.3”), although 4.1.2 defines no range at all, and clause 10 then cross-references “NOTE 1 of 4.1.2” for the discrete-tone range, which is the duplicated note rather than the NOTE 2 that states it.
• Evidence: the arithmetic above, and the Table 2/3 ranges and Figure 6 axis read side by side with NOTE 2. Verified on PDF page 10 (printed p. 2), PDF page 18 (printed p. 10), PDF page 25 (printed p. 17) and PDF page 28 (printed p. 20) of ECMA-418-1:2024 (3rd edition).
• Library behaviour: uses the internally consistent $89,1\text{Hz}$ to 11 200 Hz range (upper end exclusive per the formulas), with a code note in tonality.py.
• Status: unreported.

• Location: clause 12.3, Formula (21) (printed p. 17), the curve fit for the lower band-edge frequency $f_{1,L}$ of the lower critical band.
• The print: $f_{1,L}=C_{L,0}+C_{L,0}{f}_t+C_{L,2}{f}_t^2$.
• The problem: the linear coefficient repeats the constant term. The where-list immediately below the formula declares ”$C_{L,0}$, $C_{L,1}$, $C_{L,2}$ are constants given in Table 2”, Table 2 tabulates a $C_{L,1}$ column, and the parallel Formula (22) for the upper band edge prints $f_{2,U}=C_{U,0}+C_{U,1}{f}_t+C_{U,2}{f}_t^2$ correctly. The misprint is numerically fatal, not cosmetic: over the middle fit range ($171,4\le f_t\le 1600$) Table 2 gives $C_{L,0}=-149,5$ and $C_{L,1}=1,001$, so the printed form returns $-149,5-149,5f_t-6,90\cdot 10^{-5}{f}_t^2$, negative everywhere, instead of a band edge a little below $f_t$.
• Evidence: the formula, its own where-list and Table 2 on one page, with Formula (22) as the consistent control. Verified on PDF page 25 (printed p. 17) of ECMA-418-1:2024 (3rd edition).
• Library behaviour: implements the $C_{L,1}$ reading, which is the only one that returns a usable band edge, with a code note in tonality.py.
• Status: unreported.

• Location: clause 11.3 “Determination of masking noise level” (printed p. 12), the sentence introducing the critical bandwidth.
• The print: “The critical bandwidth Δf_c is determined from Formula Error! Reference source not found.Error! Reference source not found. with f_0 set equal to the frequency of the discrete tone under investigation, f_t”.
• The problem: two unresolved word-processor field references were typeset, in bold, in place of the formula numbers, and shipped in the published third edition. The intended targets are unambiguous from the rest of the sentence, which goes on to name Formulae (4) and (5) or (7) and (8) for the band edges: the critical bandwidth itself is Formula (2), and Formula (3) is the relation $f_2-f_1=\Delta f_c$ that turns it into band edges.
• Evidence: the clause as printed. Verified on PDF page 20 (printed p. 12), PDF page 18 (printed p. 10) and PDF page 30 (printed p. 22) of ECMA-418-1:2024 (3rd edition).
• Library behaviour: none required; the library implements the critical bandwidth from Formulae (3)/(6) directly.
• Status: unreported.

• Location: clause 5.1.5.2, the segmentation of the zero-padded signal for the roughness/fluctuation-strength block sizes.
• The print: the index of the last block is given as $l_{\text{last}}=\lceil (n+s_b)/s_h\rceil$.
• The problem: the formula is internally inconsistent: blocks placed at that index overrun the zero-padded signal defined by clause 5.1.2.2, and the resulting Formula (103) time grid becomes non-monotonic. The only self-consistent reading is to stop at the last block that fits inside the padded signal and align it flush with its end.
• Evidence: direct evaluation of the block start indices against the padded length for the clause 7.1.1 block/hop sizes; the flush-to-end reading reproduces the Clause 7 roughness calibration ($1\text{asper}$) to $0,9999$.
• Library behaviour: implements the flush-to-end reading with a code note in roughness_ecma.py.
• Status: unreported.

• Location: clause 9.1.4, Formula (127), the spectral kernel of the envelope analysis window used by the High-resolution Spectral Analysis.
• The print: the kernel’s phase factor is $\exp (-j\cdot 2\pi \cdot f_n(k)\cdot ({\tilde{s}}_b-n_{ze}+n_{zb}-1))$.
• The problem: the kernel is, by construction, the DFT of the rectangular analysis window of Formula (120) modulated to the candidate rate; that is the model Formula (124) fits to the measured DFT spectrum. That DFT has the phase $\exp (-j\cdot \pi \cdot f_n\cdot ({\tilde{s}}_b-n_{ze}+n_{zb}-1))$; the printed factor doubles it (and is also inconsistent with the $\pi$ arguments of the printed sine terms of the same formula). With the printed phase the fitted model cannot reproduce the spectrum of a noiseless windowed sinusoid, contradicting the clause’s own statement that the HSA achieves “theoretically infinite resolution for signals without noise”.
• Evidence: independent derivation of the window DFT plus numerical recomputation: with $\pi$ the least-squares fit recovers the constant part, amplitudes and phases of synthetic noiseless envelopes to machine precision and the Formula (135) residual vanishes; with the printed $2\pi$ the kernel deviates from the window DFT by amounts of the order of the kernel itself and the residual stays of the order of the signal energy.
• Library behaviour: implements the $\pi$ reading, pinned by a regression test on the exact recovery of synthetic line pairs.
• Status: unreported.

• Location: clause 9.1.5, Formula (144), the modulation rate of a local maximum of the envelope power spectrum.
• The print: the rate is the three-bin amplitude-weighted centroid of the peak position minus one, scaled by $\Delta f$.
• The problem: clause 9.1.4 (below Formula (122)) defines the spectral index $k$ as mapping to the modulation rate $k\cdot {\tilde{r}}_s/{\tilde{s}}_b$ with $k$ starting at 0. A symmetric local maximum at bin $k$ has centroid $k$, and the printed formula then assigns it the rate $(k-1)\cdot \Delta f$, one full bin ($0,73\text{Hz}$) low, which at fluctuation-strength rates is fatal (a true $1,46\text{Hz}$ modulation would be reported as $0,73\text{Hz}$). The offset is only consistent with 1-based spectral-line positions, contradicting the standard’s own definition of $k$.
• Evidence: cross-check of Formula (144) against the $k$-to-rate mapping stated below Formula (122).
• Library behaviour: uses the centroid directly (no offset) with the 0-based $k$ of Formula (122).
• Status: unreported.

• Location: clause 9.1.7, Formulae (149)-(152), the damped Newton fine tuning of the dominant modulation rate.
• The print: differential step $\Delta x=10^{-5}$, damped-step cap $2\cdot 10^{-4}$, stop tolerance $10^{-7}$ and an iteration limit of 40, with the starting point $x_0={\tilde{f}}_{c,i_{\text{max}}}$ (a rate in Hz) and the failure check $|f_{c,1,\text{opt}}-{\tilde{f}}_{c,i_{\text{max}}}|>1,25\cdot \Delta f$.
• The problem: the constants carry no units. Read in Hz, the damped step is capped at $5\cdot 10^{-5}\text{Hz}$ per iteration ($2\cdot 10^{-3}\text{Hz}$ over all 40 iterations), so the tuning cannot move appreciably and the $1,25\cdot \Delta f$ ($\approx 0,92\text{Hz}$) failure check is unreachable; the whole clause would be inert. Read as normalized modulation rates $f/{\tilde{r}}_s$ (the variable in which the Formula (127) kernel frequencies are expressed), the same constants give a $0,075\text{Hz}$ damped per-iteration cap ($\approx 2,9\text{Hz}$ over the 39 iterations), a $1,5\cdot 10^{-4}\text{Hz}$ stop tolerance and a reachable failure check, all consistent with the clause’s purpose.
• Evidence: dimensional analysis of the printed constants against the $0,7324\text{Hz}$ spectral resolution and the failure threshold.
• Library behaviour: applies the constants as normalized modulation rates.
• Status: unreported.

• Location: clause 9, third paragraph of the introduction, on the HSA-based loudness prediction.
• The print: “loudness scaling is improved by using HSA-based loudness prediction (see Clause 0)”.
• The problem: “Clause 0” does not exist; the HSA-based loudness scaling is described in clause 9.1.10 (an unresolved field reference).
• Evidence: the clause listing of the standard itself.
• Library behaviour: none required (the intended target is unambiguous).
• Status: unreported.

• Location: clause 5.3.4, Formulae (10)/(11) (printed p. 9), the minimum edge steepness of a distinct tone.
• The print: the two edges are scaled differently: $\Delta L_u=(f_T/2)\cdot (L_{T\text{max}}-L_u)/(f_T-f_u)\ge 24\text{dB}$ and $\Delta L_o=f_T\cdot (L_{T\text{max}}-L_o)/(f_o-f_T)\ge 24\text{dB}$.
• The problem: the parent standard DIN 45681:2005-03 prints $f_T/\sqrt{2}$ on both edges (Gleichungen (10)/(11), printed p. 14), and its executable Anhang J reference program does the same (Frequenz(i)/Sqr(2)). The two prints cannot both be satisfied. Neither ISO factor is the DIN one: on the lower edge $1/2<1/\sqrt{2}$, so the ISO print returns a level difference $\sqrt{2}$ smaller and is therefore stricter; on the upper edge the divisor is absent altogether, so the ISO print returns $\sqrt{2}$ larger and is more lenient. An earlier revision of this entry had the two directions the other way round and described the upper edge as “halved”, where in fact the divisor is missing rather than halved. Borderline tones with one-sided edge steepness between $24/\sqrt{2}=17$ and $24\cdot \sqrt{2}=34\text{dB/octave}$ flip classification between the two readings.
• Evidence: side-by-side comparison of the ISO print, the DIN 45681 print and the DIN Anhang J program. The DIN radicals are exactly the case the page rule exists for: pdftotext drops the √ glyph from both DIN formulae, so the extracted text reads f_T/2 and matches the ISO print, while the page itself reads f_T/√2. Verified on PDF page 13 (printed p. 9) of ISO/PAS 20065:2016 and PDF page 14 (printed p. 14) of DIN 45681:2005-03.
• Library behaviour: follows the DIN/$\sqrt{2}$ reading (it matches the only executable reference), with the choice recorded in tone_audibility.py.
• Status: unreported.

• Location: Anhang I, Beispiel I.2 (combustion engine, spectrum $j=1$), Tabelle I.6, the combined row “6 FG” for the three tones $k=6/7/8$ ($592,2$ / $629,8$ / $643,3\text{Hz}$, tone levels $78,31$ / $75,00$ / $79,75\text{dB}$).
• The print: $L_T=81,11\text{dB}$ together with $\Delta L=9,12\text{dB}$ (with $L_S=59,53$, $L_G=76,16$, $a_v=-2,40$ at $592,2\text{Hz}$).
• The problem: the two cells contradict each other. The printed $\Delta L=9,12\text{dB}$ only reproduces from the plain Formula (17) energy sum of the three tone levels ($82,8734\text{dB}$): $82,87-76,16+2,40=9,11$. The printed $L_T=81,11\text{dB}$ is that same sum less exactly $1,763\text{dB}$, and taken at face value it would give $\Delta L=7,35\text{dB}$.
• Evidence: recomputation from the printed per-tone levels of Tabelle I.6. The offset is the discriminator and it is a constant, not a deduplication: $82,8734-81,11=1,763\text{dB}$, and $1,76\text{dB}$ is $10{\log }_{10}1,5$, the standard’s own Hanning effective-bandwidth correction (clause 5.3.2). The same offset appears in the “5 FG” row of Tabelle I.10 (printed p. 46), where the two member tones at $705,2$ and $732,1\text{Hz}$ have $L_T=55,12$ and $54,23\text{dB}$, sum to $57,708\text{dB}$, and are printed as $55,95\text{dB}$, $1,758\text{dB}$ lower, and there the printed $\Delta L=3,22\text{dB}$ follows the printed $L_T$ exactly ($55,95-55,28+2,55=3,22$), so the Tabelle I.10 row is internally consistent and the Tabelle I.6 row is not. The third combined row, “2 FG” of the same Tabelle I.6, carries no offset at all: its three member levels $64,56$ / $67,96$ / $68,63\text{dB}$ sum to $72,149\text{dB}$ against a printed $72,15\text{dB}$, and its $\Delta L$ follows. A previous revision of this entry attributed the $81,11\text{dB}$ cell to the Anmerkung 2 shared-line deduplication; that diagnosis is unsupported, because a deduplication removes an arbitrary amount of energy while all the offsets observed here are the same 1,76 dB. Verified on PDF page 41 (printed p. 41) and PDF page 46 (printed p. 46) of DIN 45681:2005-03.
• Library behaviour: combined_tone_level follows Anmerkung 2 (shared lines counted once), which reproduces the printed “2 FG” oracle; for the “6 FG” row only the $\Delta L$ chain is pinned, with the contradiction recorded in tests/reference_data/.
• Status: unreported.

• Location: Anhang I, the column headers of Tabelle I.2 (printed p. 37, spectrum $j=2$) and Tabelle I.10 (printed p. 46, spectrum $j=24$).
• The print: every column of Tabelle I.2 is subscripted with the spectrum index 2 (f_T 2,k, f_1 2,k, f_2 2,k, L_S 2,k, L_T 2,k, L_G 2,k, a_v 2,k, u_2,k) except the audibility column, which is headed ΔL_1,k. Every column of Tabelle I.10 is subscripted 24 (f_T 24,k, ΔL 24,k, f_1 24,k, f_2 24,k, L_S 24,k, L_T 24,k, L_G 24,k, u 24,k) except the masking column, which is headed a_v 1,k.
• The problem: both tables carry the spectrum index of the first spectrum in one column. Tabelle I.2’s own caption reads “des zweiten Spektrums (j = 2)” and Tabelle I.10’s “des 24. Spektrums (j = 24)”, and the body values belong to those spectra: the $\Delta L$ column of Tabelle I.2 is the audibility of the $j=2$ tones ($8,53\text{dB}$ at $627,2\text{Hz}$, which the Anmerkung below the table calls “die maßgebliche Differenz ΔL_2”), and the $a_v$ column of Tabelle I.10 is the masking index of the $j=24$ tones. The index 1 is right in exactly one table of the annex, Tabelle I.6, which is the $j=1$ table of Beispiel I.2 and carries both ΔL_1,k and a_v 1,k legitimately.
• Evidence: the tables’ own captions, their neighbouring column subscripts, and the Anmerkung under each. Verified on PDF page 37 (printed p. 37), PDF page 46 (printed p. 46), and PDF page 41 (printed p. 41) of DIN 45681:2005-03.
• Library behaviour: none needed; the numbers are unaffected. The regression fixtures index both tables by their caption’s spectrum.
• Status: unreported.

• Location: Appendix A, “Noise weighting network and quasi-peak meter”, Figure A1 “Weighting network” (printed p. 29), drawing 0641/85. The French print of the same artwork (printed p. 28) carries the same value as 41,47 nF.
• The print: the last shunt capacitor of the ladder, the one across the 600 Ω amplifier input, is labelled 41.47 nF.
• The problem: it should be 31.47 nF, which is what ITU-R BS.468-4 Figure 1a prints for the same network. Every other element of Figure A1 matches BS.468-4 Figure 1a exactly: 600 Ω source, 13.85 nF, 12.88 mH, 26.82 nF, 33.06 nF, 9.21 nF, 26.49 mH and Z = 600 Ω. The intended reading is not in doubt, because the document contradicts itself: evaluated against Table AI, printed two pages earlier in the same annex, the 31.47 nF ladder reproduces all 21 rows to a maximum of 0.050 dB and violates no tolerance, while the 41.47 nF ladder is out by up to 2.252 dB (at 31 500 Hz) with a root-mean-square error of 1.055 dB and breaks Table AI’s own tolerance column at seven frequencies, every one from 8 000 Hz to 20 000 Hz: −0.40 dB against ±0.40 at 8 kHz, −0.74 against ±0.60 at 9 kHz, −1.16 against ±0.80 at 10 kHz, −1.85 against ±1.20 at 12.5 kHz, −1.98 against ±1.40 at 14 kHz, −2.05 against ±1.60 at 16 kHz and −2.12 against ±2.00 at 20 kHz. Sweeping the capacitor to minimise the error against Table AI lands on 31.4798 nF.
• Evidence: the two ladders evaluated independently by an ABCD chain product over the seven printed reactive elements between the printed 600 Ω source and load, normalised at 1 kHz, and compared row by row with Table AI and its tolerance column. Neither Amendment 1:1988 (which replaces Table AII only) nor Amendment 2:1988 (which replaces sub-clause 12.1, on producing a uniform alternating magnetic field) touches Figure A1, so the misprint stands in the current document as amended. Verified on PDF page 31 (printed p. 29) and PDF page 29 (printed p. 27), which carries Table AI, of IEC 60268-1:1985, and on PDF page 1 (printed p. 1) of Recommendation ITU-R BS.468-4.
• Library behaviour: unaffected. The weighting network is built from the BS.468-4 Figure 1a component values in filters/weighting.py, with 31.47 nF, and the Table 1 rows are the oracle. The entry matters because IEC 60268-3:2013 sub-clause 14.12.11 sends a reader to “a weighting network complying with Appendix A of IEC 60268-1”, so a clean-room implementation started from IEC 60268-3 lands on the wrong capacitor.
• Status: unreported.

• Location: Appendix A, Table AII, the tone-burst dynamic characteristic of the quasi-peak meter, “Limited values — lower limit” row (printed p. 31).
• The print: the lower limit (%) row reads 13.5 | 22.4 | 34 | 41 | 44 | 44 | 50 | 68 for the 1, 2, 5, 10, 20, 50, 100 and 200 ms columns, while the (dB) row printed immediately beneath it reads −17.4 | −13.0 | −9.3 | −7.7 | −7.1 | −6.0 | −4.7 | −3.3.
• The problem: the 50 ms and 100 ms cells contradict their own dB cells. −6.0 dB is 50.1 %, not 44 %, and −4.7 dB is 58.2 %, not 50 %. The percentage row has slipped one column to the right from 50 ms onwards, carrying the 20 ms and 50 ms values into the two cells after them; the dB row and the 200 ms cell stayed where they belong. ITU-R BS.468-4 Table 2 prints ... | 44 | 50 | 58 | 68 for the same four columns.
• Evidence: the two rows of the same table read against each other, and against the corresponding row of ITU-R BS.468-4 Table 2. Corrected by Amendment 1:1988-01, whose English sheet is headed “Page 31 / Replace Table AII by the following:” and prints the lower limit row as 13.5 | 22.4 | 34 | 41 | 44 | 50 | 58 | 68, matching BS.468-4; every other cell of the replacement table is identical to the base print, so this row is the entire substantive content of the amendment. Verified on PDF page 33 (printed p. 31) of IEC 60268-1:1985, on PDF page 3 (printed p. 3) of IEC 60268-1:1985 Amendment 1:1988, and on PDF page 4 (printed p. 4) of Recommendation ITU-R BS.468-4.
• Library behaviour: unaffected. The eleven acceptance windows are transcribed from BS.468-4 Tables 2 and 3 in tests/reference_data/, which agree with the amended IEC table. Recorded because the unamended base document is the one a reader is likely to hold, and it widens the 50 ms and 100 ms acceptance windows by 1.1 dB and 1.3 dB at the bottom.
• Status: unreported (corrected by the issuing body in 1988).

• Location: clause 2.1, Table 2, “Limiting values — upper limit”, the 5 ms column (printed p. 4). The same pair of cells is printed identically in IEC 60268-1:1985 Table AII and in the Amendment 1:1988 table that replaces it, so the defect is inherited from the CCIR text rather than introduced by either edition.
• The print: 46 in the (%) row and −6.6 in the (dB) row.
• The problem: the two disagree. 46 % is 20 lg(0.46) = −6.745 dB, and −6.6 dB is 46.8 %. All 33 cells of Tables 2 and 3 were audited against their own counterpart; 32 agree to within 0.050 dB, the rounding of a two-significant-figure percentage, and this one is out by 0.145 dB. The neighbouring 5 ms lower limit (34, −9.3) is out by 0.070 dB and is benign, because 34 % as a rounded two-figure percentage covers 33.5 % to 34.5 %, that is −9.500 dB to −9.241 dB, and −9.3 lies inside it. The upper cell is not benign: 46 % covers 45.5 % to 46.5 %, that is −6.840 dB to −6.651 dB, which excludes −6.6.
• Which cell is wrong: the dB one. Read as percentages, the acceptance window is a very steady −1.4 dB / +1.2 dB about the reference reading for every duration from 5 ms to 200 ms (+1.18 to +1.24 dB above, −1.37 to −1.45 dB below). 46 % puts the 5 ms upper limit +1.214 dB above its reference, on that pattern; 46.774 %, which is what −6.6 dB means, would put it +1.360 dB above, off it. So 46 % is right and the dB cell should read −6.7.
• Evidence: 20 lg of each printed percentage compared with the printed dB cell beside it, for all 24 cells of Table 2 and all 9 of Table 3, and the upper- and lower-limit offsets about the reference row recomputed across the five durations from 5 ms to 200 ms. Verified on PDF page 4 (printed p. 4) of Recommendation ITU-R BS.468-4, on PDF page 33 (printed p. 31) of IEC 60268-1:1985, and on PDF page 3 (printed p. 3) of IEC 60268-1:1985 Amendment 1:1988.
• Library behaviour: the percentage rows are primary and the dB rows are derived from them, which is the decision this entry forces. The eleven acceptance windows are stored as percentages in tests/reference_data/ and checked as percentages, in the test suite and in the conformance rows “ITU-R BS.468-4 Table 2” and “ITU-R BS.468-4 Table 3”.
• Status: unreported.

• Location: Appendix A, Table AI, the tolerance column, 16 000 Hz row (printed p. 27; the French Tableau AI on printed p. 26 prints the same value).
• The print: ±1.65 1).
• The problem: ITU-R BS.468-4 Table 1 and AES17-2015 Table 1 both print ±1.6 for the same row, and the table’s own footnote 1) is what settles it: the marked tolerances “are obtained by a linear interpolation on a logarithmic graph on the basis of values specified for the frequencies used to define the mask, i.e. 31.5 Hz, 100 Hz, 1 000 Hz, 5 000 Hz, 6 300 Hz, and 20 000 Hz”. Interpolated on that rule between (6 300 Hz, 0 dB) and (20 000 Hz, ±2.0 dB), 16 000 Hz gives 1.6137 dB, which rounds to 1.6 at one decimal and to 1.61 at two. No rounding of the rule produces 1.65, and no alternative anchor pair does either: taking the 6 300 Hz to 31 500 Hz line instead gives 1.6216 dB. The value is also anomalous within its own column, which is quoted to one decimal everywhere else.
• Evidence: the footnote rule applied to all 14 marked rows of the same column, which reproduces every one of them (63 Hz 1.400, 200 Hz 0.8495, 400 Hz 0.6990, 800 Hz 0.5485, 3 150 and 4 000 Hz 0.5000, 7 100 Hz 0.2070, 8 000 Hz 0.4136, 9 000 Hz 0.6175, 10 000 Hz 0.7999, 12 500 Hz 1.1863, 14 000 Hz 1.3825, 31 500 Hz 2.7865) and 16 000 Hz alone disagrees with what is printed. Not corrected by Amendment 1:1988 or Amendment 2:1988. Verified on PDF page 29 (printed p. 27) of IEC 60268-1:1985 and on PDF page 2 (printed p. 2) of Recommendation ITU-R BS.468-4.
• Library behaviour: none needed. The tolerance mask is taken from BS.468-4 Table 1, and the realised digital curve is held to a far tighter bound than the mask anyway: the mask governs a measuring instrument comprising the amplifier and the network, not a filter’s departure from the nominal curve.
• Status: unreported.

• Location: clause 14.12.9.2, item f) (printed p. 39), the formula for the dynamic intermodulation distortion $d_{\text{DIM}}$.
• The print: $d_{\text{DIM}}=({\sum }_{i=1}^9{U_i^{\prime }}^2{)}^{1/2}/U_2\times 100\%$.
• The problem: the denominator is one of the nine terms of its own numerator. Table 2 of the same clause (printed p. 38) defines $U_2$ as the intermodulation component at $f_s-2f_q=8,70\text{kHz}$, and item d) defines $U_1,U_2,\dots U_i$ as exactly those components, so the sum $i=1\dots 9$ runs over $U_1\dots U_9$ and includes $U_2$. Meanwhile the defining clause 14.12.9.1 states the ratio of the r.m.s. sum of the Table 2 intermodulation product voltages “to the amplitude of the output voltage at the frequency f_s”, i.e. the 15 kHz sine component $U_s$, the Otala convention, and item d) measures “the amplitudes of the sinusoidal signal $U_s$” precisely so that it can be used, which the f) formula then never does. The denominator should be $U_s$. An earlier revision of this entry said that “U2 is used throughout 14.12 for the total output voltage”; that is false, in both the English and the French print.
• Evidence: Table 2, item d) and item f) read together in both language columns of the bilingual edition; the historical DIM literature (Otala) defines the ratio to the sine amplitude. Verified on PDF page 41 (printed p. 39), PDF page 40 (printed p. 38), which carries Table 2, and PDF page 102 (printed p. 100), which carries the same item f) in the French column, of IEC 60268-3:2013.
• Library behaviour: follows the 14.12.9.1 definition (reference = the output amplitude at $f_s$), with a code comment at the reference measurement in distortion.py.
• Status: unreported.

• Location: Annex M, Table M.1 “Example calculation”, step 4, the row labelled “Sum of beta*$MTI$ = $MT{I}_k$ $\times$ beta weighting” (printed p. 67), directly below the matching alpha row.
• The print: the label reads $MT{I}_k\times {\beta }_k$, and the seven cells of the row read 0,059 | 0,052 | 0,045 | 0,008 | 0,037 | 0,081 | 0,000, summed on the next page as $\sum \text{beta*}MTI=0,282$.
• The problem: the label and the cells state different quantities, and the label is the one that is wrong. Clause A.5.6 of the same edition (printed p. 47) defines the index as $STI={\sum }_{k=1}^7{\alpha }_k\times MT{I}_k-{\sum }_{k=1}^6{\beta }_k\times \sqrt{MT{I}_k\times MT{I}_{k+1}}$: the redundancy term is the geometric mean of two adjacent bands, not the band’s own $MT{I}_k$. Read against the table’s own MTI row, ${\beta }_k\times MT{I}_k$ gives 0,062 | 0,051 | 0,044 | 0,008 | 0,036 | 0,076, summing to 0,277, which disagrees with five of the six printed cells and with the printed total. ${\beta }_k\sqrt{MT{I}_{k}MT{I}_{k+1}}$ reproduces all six cells and the 0,282 total. The seventh cell is not part of either reading: the redundancy sum stops at $k=6$ because the 8 kHz band has no band above it to pair with, so its 0,000 is the placeholder of a column with no redundancy partner, not a term. The alpha row above it, labelled the same way, is correct, because there the label and A.5.6 do agree.
• Evidence: both readings recomputed from the table’s own step 4c MTI row and compared cell by cell with the printed row and with its printed total; A.5.6 read against the label. The defect does not move this example’s answer, since $1,040-0,277=0,763$ and $1,040-0,282=0,758$ both print as the STI 0,76 the table ends on, which is how a label contradicting the normative formula survives a worked example. Verified on PDF page 69 (printed p. 67) and PDF page 49 (printed p. 47) of IEC 60268-16:2011.
• Library behaviour: implements A.5.6 with the redundancy term as printed there, in _index_from_corrected_mtf; the pairwise weighting-factor test of A.2.2 pins it independently, and the conformance rows “IEC 60268-16:2020 A.2.2” and “IEC 60268-16 Annex M” both read the index it produces.
• Status: unreported.

• Location: Annex M, Table M.1, the row “Combined squared sound pressure $I_k$, MPa${}^2$” of step 2 (printed p. 64) and of step 3 (printed p. 65), read with the $I_{am,k}$ and $I_{rt,k}$ rows below it.
• The print: for the 77,9 dB signal of the 125 Hz band, step 2 prints $I_k$ = 61,7, and four rows below it prints $I_{rt,k}$ = 40 000 for the 46 dB reception threshold of the same band.
• The problem: two defects in one row. The unit is impossible: at 77,9 dB re 20 µPa the squared sound pressure is $0,0247{\text{Pa}}^2$, so the cell cannot be 61,7 MPa${}^2$ under any reading of the prefix. What the row actually tabulates is the dimensionless intensity ratio $10^{L/10}=61722596$ divided by $10^6$. And that divisor is not applied to the two quantities the standard adds to $I_k$ in the very next rows: $I_{am,k}$ and $I_{rt,k}$ are tabulated as the plain ratio, 40 000 being $10^{4,6}=39811$ rounded, undivided. A reader who forms $I_k+I_{am,k}+I_{rt,k}$ from the cells as printed understates its first term by $10^6$. The printed “adjustment to remove masking and threshold” row is the check: 1,019 at 500 Hz is $(I_k+I_{am,k}+I_{rt,k})/I_k$ only once $I_k$ is restored to 26 305 192; formed from the cells as printed the same expression reads 19 279.
• Evidence: every cell of both $I_k$ rows recomputed as $10^{L/10}$ from the combined levels printed above them, and every cell of the $I_{am,k}$ and $I_{rt,k}$ rows recomputed as $am{f}_k\times I_{k-1}$ and $10^{AR{T}_k/10}$; the first set reproduces at $10^{-6}$ of the computed value and the second two at $10^0$. Verified on PDF page 66 (printed p. 64) and PDF page 67 (printed p. 65) of IEC 60268-16:2011.
• Library behaviour: carries all three quantities on one scale, the plain ratio to $p_0^2=(20\mu \text{Pa}{)}^2$, in the correction of sti.py; the transcription in tests/reference_data/ keeps the printed cells verbatim and names the $10^6$ it rescales them by, and the conformance row “IEC 60268-16 Annex M” reads the adjustment they feed.
• Status: unreported.

• Location: Annex M, Table M.1, step 3, the $I_{am,k}$ row, 250 Hz column (printed p. 65).
• The print: 2 850 000, the same value as the 500 Hz cell beside it.
• The problem: the cell does not round from the quantity it names. With the operational levels printed two rows above, $I_{am,k}$ at 250 Hz is the auditory masking factor of the 125 Hz band times that band’s combined intensity, $0,01463507\times 195339273=2858804$, which at the three significant figures the row is printed to reads 2 860 000. The 500 Hz cell is correct: its 2 852 252 does print as 2 850 000. The two cells are reproduced together only by carrying the rounded $amf\times 1000=14,6$ of the row above instead of the factor itself, and step 2 shows that is not what the table does, since its two corresponding cells are printed apart, as 508 000 and 507 000, which only the unrounded factor gives.
• Evidence: both cells recomputed from the printed operational speech and noise levels, and the step 2 pair recomputed the same way as a control. The defect changes nothing downstream: the masking and threshold correction of the band is 0,985552 with the correct value against 0,985596 with the printed one, and the row prints 0,986 either way. Verified on PDF page 67 (printed p. 65) and PDF page 66 (printed p. 64) of IEC 60268-16:2011.
• Library behaviour: computes $I_{am,k}$ from the unrounded masking factor. The transcription in tests/reference_data/ keeps the printed cell and the test test_annex_m_step3_masking_intensity_at_250_hz_is_the_printed_erratum asserts the computed value against 2 858 804 and against the print, so the one cell of the table that is not an oracle cannot quietly become one.
• Status: unreported.

• Location: clause 6.1 “Rango de frecuencias”, the class 2 sentence, of UNE-EN 61043 (April 1999), which declares itself “la versión oficial, en español, de la Norma Europea EN 61043 de enero 1994, que a su vez adopta la Norma Internacional CEI 61043:1993”.
• The print: a single sentence, “Los procesadores de clase 2 deberán cubrir, al menos, el rango desde 45 Hz a 5,6 kHz en bandas de octava.”
• The problem: the EN/IEC text gives class 2 processors two alternative ranges, not one: “Class 2 processors shall, at least, cover the range from 45 Hz to 7,1 kHz in one-third octave bands, or the range from 45 Hz to 5,6 kHz in one octave bands” (BS EN 61043:1994, clause 6.1). The translation drops the first alternative. The omission is normative rather than editorial: it removes one of the two ways clause 6.1 can be satisfied, and a reader of the Spanish text alone would conclude that class 2 is defined over octave bands, so that a one-third-octave chain verified over the 22 tabulated bands from 50 Hz to $6,3\text{kHz}$ could not attest class 2 over its full range.
• Evidence: side-by-side reading of clause 6.1 in both prints. The class 1 sentence is word-for-word equivalent in the two documents, so the divergence is confined to the class 2 sentence. The Spanish print also contradicts itself: its Table 2 tabulates the pressure-residual intensity index for class 2 processors at all 22 one-third-octave centres, and its faithfully translated Note 2 (“Para procesadores con análisis en bandas de octavas únicamente, los requisitos se aplican únicamente a las frecuencias centrales de las bandas de octava”) carves out octave-only processors as a special case. Both are redundant if every class 2 processor is an octave-band one.
• Library behaviour: implements the EN/IEC reading. verify_intensity_class treats the full 22-band one-third-octave set as attesting either class, and the 7-band octave set (63 Hz to 4 kHz) as a class 2 alternative that never attests class 1, with both branches pinned by regression tests (tests/emission/test_intensity_compliance.py).
• Status: unreported (national translation, not the issuing body’s text).

• Location: clause 9.1, the symbol list under Formula (11) $P_i=I_{\mathrm{n}i}\cdot S_i$, of UNE-EN ISO 9614-1 (March 2010), which declares itself “la versión en español de la Norma Europea EN ISO 9614-1:2009”, the European adoption of ISO 9614-1:1993.
• The print: ”$I_{\mathrm{n}i}$ es el módulo de la componente de la intensidad acústica normal medida en la posición $i$ sobre la superficie de medida”. The ISO original reads ”$I_{\mathrm{n}i}$ is the signed magnitude of the normal sound intensity component measured at position $i$ on the measurement surface”.
• The problem: módulo is the absolute value, so the qualifier that carried the sign is gone, and the sign is what the rest of the method turns on. The Spanish print then contradicts itself twice over. The same clause 9.1 gives, two paragraphs below that line, the conversion to apply when the level of a position is written $(-)XX$ dB: $I_{\mathrm{n}i}=-I_0\times 10^{XX/10}$, a negative $I_{\mathrm{n}i}$. Clause 3.6.1, which defines the very quantity Formula (11) computes, calls $I_{\mathrm{n}i}$ “la componente normal, con su signo, de la intensidad acústica medida en la posición $i$”, and A.2.3 calls it “el valor algebraico de la componente de intensidad acústica normal”. And clause 9.2 makes ${\sum }_i{P}_i$ being negative the condition that puts a frequency band outside the method, which no sum of magnitudes and positive areas can ever be. Read as a magnitude the method loses the one thing measurement at discrete points is for: separating the energy leaving the source from the energy flowing back in through part of the surface, which is what $F_3$ (Formulae (A.6) and (A.7)) and $F_4$ (Formulae (A.8) and (A.9)) are built to quantify from the algebraic mean of the same $I_{\mathrm{n}i}$.
• Evidence: the two prints of the same symbol list, set side by side, and the three Spanish clauses read against one another. PDF pages 10, 18 and 22 (printed pp. 10, 18 and 22) of UNE-EN ISO 9614-1:2010; PDF page 12 (printed p. 7) of ISO 9614-1:1993, where the qualifier is present.
• Library behaviour: implements the signed reading throughout, which is the ISO text. sound_power_intensity_points sums signed partial powers, flags the bands whose sum is not positive as outside the method, and reports $F_3-F_2$ as the excess the inward flow produces; normal_intensity_from_levels carries the $(-)$ of the print as a separate argument, because the printed level never holds it. Pinned by test_a_genuinely_negative_partial_power_is_kept_and_summed and the signed conversion tests in tests/emission/test_sound_power_intensity_points.py.
• Status: unreported (national translation, not the issuing body’s text: a reader working from the ISO edition has nothing to work around).

• Location: Annex A, clause A.2.3, the “donde” list under Formula (A.6) $F_3=\overline{L_p}-\overline{L_{I_{\mathrm{n}}}}$.
• The print: the second entry of the list is typeset $\overline{L_{|I_{\mathrm{n}}|}}$, with the absolute-value bars, and reads “es el valor algebraico del nivel de intensidad acústica superficial, en decibelios, calculado a partir de la ecuación (A.7)”. Formula (A.7), three lines below on the same page, is labelled $\overline{L_{I_{\mathrm{n}}}}$, without the bars.
• The problem: the barred symbol is A.2.2’s, the level of the mean magnitude of Formula (A.5), which is exactly what $F_2$ subtracts. With the bars, $F_3$ and $F_2$ would be the same indicator and the whole of A.2.3 would be redundant; the sentence beside the symbol says “valor algebraico” and points at (A.7), which takes the algebraic mean. The ISO original prints the same entry without the bars and describes it as “the surface normal signed intensity level”, so the bars are the translation’s own typesetting.
• Evidence: the symbol as set in the two editions, and the barless (A.7) on the same page as the barred entry. PDF page 22 (printed p. 22) of UNE-EN ISO 9614-1:2010; PDF page 15 (printed p. 10) of ISO 9614-1:1993.
• Library behaviour: none required. field_indicators in intensity.py forms $F_3$ from the algebraic mean of Formula (A.7) and $F_2$ from the mean magnitude of Formula (A.5), which is what makes $F_3-F_2$ the inward-flow excess the Annex B gate is written on. Registered as a label defect.
• Status: unreported (national translation, not the issuing body’s text).

• Location: Annex B, clause B.1.3, the sentence introducing the two separate evaluations of $F_4$ that Formula (B.4) consumes.
• The print: “Calculate indicator $F_4$ separately according to A.2.3”, over the two items “a) for the segment subset $N_{\alpha }$ having total area $S_{\alpha }$, and” and “b) for the remaining segments”. The Spanish edition renders the same clause number: “Calcular el indicador $F_4$ separadamente de acuerdo al apartado A.2.3 para: a) el subconjunto de segmentos $N_{\alpha }$ con área total $S_{\alpha }$, y b) los segmentos restantes.”
• The problem: A.2.3 is “Negative partial power indicator”, which defines $F_3$ by Formulae (A.6) and (A.7). $F_4$ is A.2.4, “Field non-uniformity indicator”, Formulae (A.8) and (A.9). Followed as printed, the reference computes the wrong indicator for $F_4(\alpha )$ and $F_4(1-\alpha )$, and those are what size the new positions in Formula (B.4). Both editions carry the same clause numbering, so the defect is the issuing body’s.
• Evidence: the reference and the headings of A.2.3 and A.2.4 read against each other. PDF pages 18 and 15 to 16 (printed pp. 13 and 10 to 11) of ISO 9614-1:1993; the same sentence at PDF page 24 (printed p. 24) of UNE-EN ISO 9614-1:2010.
• Library behaviour: follows the intended target. $F_4(\alpha )$ and $F_4(1-\alpha )$ are computed per A.2.4 in partial_power_concentration. The reference changes no number the library reports, so no other change was needed.
• Status: unreported (cross-reference defect, no numerical consequence).

• Location: clause 10.5 c), “Datos acústicos”, the reporting requirement that accompanies the level of a band which does not satisfy criterion 2.
• The print: “Una referencia a la incertidumbre prevista en el nivel de potencia acústica determinada para cada banda de frecuencia en la que no se satisfaga el criterio 2 del anexo B, de acuerdo a la ecuación (véase el capítulo B.3).” The ISO original reads “A statement of the predicted uncertainty in the sound power level determined for each frequency band, in which criterion 2 of annex B is not satisfied, according to equation (B.3).”
• The problem: the number that identified the equation has been moved into a cross-reference and changed on the way. “De acuerdo a la ecuación ( )” names no equation, and what the parenthesis names instead is not part of the document: Annex B divides into B.1, with B.1.1 to B.1.5, and B.2, and stops there, so there is no chapter B.3 to look up. The requirement is unusable as printed unless the reader recognises Formula (B.3), the 95 % confidence interval $10\lg (1\pm 2F_4/\sqrt{N})$, which clause B.1.2 introduces with this very condition attached to it.
• Evidence: the two prints of the same item, and the divisions of Annex B as its headings run. PDF pages 20 and 23 to 26 (printed pp. 20 and 23 to 26) of UNE-EN ISO 9614-1:2010; PDF page 14 (printed p. 9) of ISO 9614-1:1993, where the equation number is present.
• Library behaviour: reports the interval of Formula (B.3) for every band, so the statement clause 10.5 c) asks for can be made about any band that needs it. confidence_interval on DiscretePointIntensityResult carries the pair, and criterion_2 says which bands the requirement applies to. The defect changes no number, only where a reader is sent to find the formula.
• Status: unreported (national translation, not the issuing body’s text).

• Location: Table B.3, “Actions to be taken to increase grade of accuracy of determination”, the criterion cells of the action-c and action-d rows.
• The print: action c is conditioned on “Criterion 2 not satisfied and 1 dB $\le (F_3-F_2)\le$ 3 dB”; action d on “Criterion 2 not satisfied and $(F_3-F_2)\le$ 1 dB, and the procedure of 8.3.2 either fails or is not selected”. Both inequalities are printed non-strict, in both editions.
• The problem: the two rows overlap at exactly $F_3-F_2=1$ dB, where the table prescribes two different actions for one state: increase the density of positions uniformly (c), or move the surface out and keep the positions (d). A normative decision table is not implementable while that holds. The document settles it elsewhere: Figure B.1’s fifth decision diamond is ”$(F_3-F_2)\le$ 1 dB ?”, and its Yes branch is the one that leads to the optional procedure and to action d, so 1 dB belongs to d and c begins above it. Clause 8.3.2 agrees, opening the optional procedure “if $F_3-F_2\le$ 1 dB”.
• Evidence: the two criterion cells, the diamond and its branches, and the clause 8.3.2 condition. PDF pages 19, 20 and 12 (printed pp. 14, 15 and 7) of ISO 9614-1:1993; the same three places at PDF pages 26, 27 and 17 (printed pp. 26, 27 and 17) of UNE-EN ISO 9614-1:2010.
• Library behaviour: follows Figure B.1 and clause 8.3.2. required_actions on DiscretePointIntensityResult answers a band that fails criterion 2 with action c above 1 dB and action d at 1 dB and below, pinned at the boundary itself by test_action_d_is_the_action_at_exactly_one_decibel in tests/emission/test_sound_power_intensity_points.py.
• Status: unreported.

• Location: Annex A, clause A.2.1, equation (A.1) for the temporal variability indicator $F_1$, and clause A.2.4, equation (A.8) for the field non-uniformity indicator $F_4$.
• The print: both equations open with the factor $1/I_{\mathrm{n}}$, an unbarred symbol, while the deviation inside the sum is written against a clearly overbarred $\overline{I_{\mathrm{n}}}$: $F_1=\frac{1}{I_{\mathrm{n}}}\sqrt{\frac{1}{M-1}{\sum }_k(I_{\mathrm{n}k}-\overline{I_{\mathrm{n}}}{)}^2}$ and $F_4=\frac{1}{I_{\mathrm{n}}}\sqrt{\frac{1}{N-1}{\sum }_i(I_{\mathrm{n}i}-\overline{I_{\mathrm{n}}}{)}^2}$. Both editions set them the same way.
• The problem: the symbol lists that follow define only the overbarred one (”$\overline{I_{\mathrm{n}}}$ is the mean value of $I_{\mathrm{n}}$ for $M$ short-time-average samples”, A.2.1; ”$\overline{I_{\mathrm{n}}}$ is the surface normal sound intensity calculated from equation (A.9)”, A.2.4). The unbarred $I_{\mathrm{n}}$ is clause 3.4’s normal intensity at a point, so as printed a coefficient of variation is divided by an unspecified single value rather than by the mean its own numerator is taken about. Both indicators are coefficients of variation and admit no other normalization.
• Evidence: the two equations and the symbol lists beneath them, where the bar is absent above the divisor and unbroken above the symbol inside the sum. PDF pages 15 and 16 (printed pp. 10 and 11) of ISO 9614-1:1993; the same two equations at PDF pages 21 and 22 (printed pp. 21 and 22) of UNE-EN ISO 9614-1:2010.
• Library behaviour: none required. The coefficient of variation behind field_indicators and temporal_variability_indicator in intensity.py divides by the algebraic mean, and refuses a mean that is not positive rather than dividing by it. Registered as a typographic defect.
• Status: unreported (typographic).

• Location: Note 11, immediately after the Formula (B.4) block of clause B.1.3, which qualifies the choice of the Table B.2 factor $C$ for an A-weighted determination.
• The print: “Si la contribución total al nivel de potencia acústica ponderado A de las bandas de tercio de octava en el margen de frecuencias de 800 Hz a 5 000 Hz es menos de la mitad del nivel total, entonces deben usarse los valores de $C$ para las bandas de tercio de octava de 200 Hz a 630 Hz.” The ISO original reads “If the total contribution to the A-weighted sound power from the one-third-octave bands in the frequency range 800 Hz to 5 000 Hz is less than half the total power, then the values of $C$ for the one-third-octave band 200 Hz to 630 Hz should be used.”
• The problem: two departures in one sentence. Half of a level is not a defined operation, so the Spanish print states a condition that cannot be evaluated as written; the original conditions on half the power, which is a contribution 3 dB or more below the total and is decidable. And should, a recommendation under the ISO/IEC drafting rules, becomes deben, which reads as a requirement, so the two prints do not even agree on whether the substitution is optional.
• Evidence: the two prints of the same note. PDF page 25 (printed p. 25) of UNE-EN ISO 9614-1:2010; PDF page 18 (printed p. 13) of ISO 9614-1:1993.
• Library behaviour: implements the power reading, and applies the substitution whenever the condition holds rather than leaving it to the caller, which satisfies both prints. _a_weighted_factor in sound_power_intensity_points.py compares the summed A-weighted contribution of the 800 Hz to 5 kHz bands with half the total contribution and reads the 200 Hz to 630 Hz row of Table B.2 when it falls short.
• Status: unreported (national translation, not the issuing body’s text).

• Location: clause 8.3.4, Equation (21) and the symbol list beneath it (PDF page 31, printed p. 25) of ISO 3744:2010, read against the definitions of clauses 3.3 and 3.4 (PDF page 9, printed p. 3). The same construction is printed as ISO 3741:2010 Equation (25) (PDF page 33, printed p. 24, with its symbol list on PDF page 34, printed p. 25) as ISO 3747:2010 Equation (14) (PDF pages 22 and 23, printed pp. 13 and 14), and as ISO 3746:2010 Equation (15) in clause 8.4.2 (PDF page 25, printed p. 16), which is the survey-grade route the library takes for grade='survey'.
• The print: $K_1=-10\lg \left(1-10^{-0,1\Delta L_E}\right)$ dB with $\Delta L_E=\overline{L_{E(\mathrm{ST})}^{\prime }}-\overline{L_{p(\mathrm{B})}}$, where $\overline{L_{E(\mathrm{ST})}^{\prime }}$ “is the mean frequency-band or A-weighted single event time-integrated sound pressure level” and $\overline{L_{p(\mathrm{B})}}$ “is the mean frequency-band or A-weighted time-averaged sound pressure level of the background noise”, followed by “The integration time $T=t_2-t_1$ and other measurement parameters shall be the same for the measurement of the single event time-integrated sound pressure level $L_{Ei(\mathrm{ST})}^{\prime }$ and of the background noise level $L_{pi(\mathrm{B})}$.”
• The problem: the two levels do not share a reference quantity, and the correction subtracts one energy from another. By clause 3.4, $L_E$ is ${\int }_{t_1}^{t_2}{p}^2\mathrm{d}t$ re $E_0=(20\mu \text{Pa}{)}^2\text{s}$; by clause 3.3, $L_{p,T}$ is $\frac{1}{T}{\int }_{t_1}^{t_2}{p}^2\mathrm{d}t$ re $p_0^2$. Their difference is a ratio of energies only when $T=1$ s. Over the common interval $T$ the background contributes the energy $L_{p(\mathrm{B})}+10\lg (T/T_0)$ (the identity of clause 3.4 NOTE 1), so the printed $\Delta L_E$ exceeds the signal-to-background energy ratio by $10\lg (T/T_0)$ and $K_1$ is under-estimated for every $T>1$ s: a burst whose energy is 6 dB above the background’s in a 10 s interval reads as 16 dB above it and earns no correction, where the criterion of 8.2.3 puts $K_1$ at its largest admissible value, 1,3 dB. The twin chain of 8.2, where both levels are time-averaged, has no such term, and 8.3.3 requires the single event levels to be averaged “in the same way as for the time-averaged sound pressure levels described in 8.2.2”, so the intended reading is the one under which the two chains coincide for a source that is steady over $T$, $L_J=L_W+10\lg (T/T_0)$, and that is the reading under which the insistence on one integration time for both measurements does any work.
• Evidence: Verified on PDF page 31 (printed p. 25) of ISO 3744:2010 for the equation and its symbol list, and on PDF page 9 (printed p. 3) for the definitions of clauses 3.3 and 3.4 with NOTE 1; the same construction read on PDF pages 33 and 34 (printed pp. 24 and 25) of BS EN ISO 3741:2010 and on PDF pages 22 and 23 (printed pp. 13 and 14) of BS EN ISO 3747:2010.
• Library behaviour: sound_energy_pressure, sound_energy_reverberation and sound_energy_comparison compare the background as its exposure over the same interval, $L_{p(\mathrm{B})}+10\lg (T/T_0)$, and require integration_time with the background of the source under test, which is the one compared against an event level. The reference source of sound_energy_comparison is steady, so background_levels_ref is corrected by the time-averaged rule of 9.1.2 instead and takes no window; the criteria and the clamp of 8.2.3 (and of 9.1.2 in ISO 3741) are then applied to that margin. tests/emission/test_sound_energy.py pins $K_1=1,2563$ dB for a 78 dB burst over a 62 dB background in a 10 s window, and $L_J=L_W+10\lg (T/T_0)$ field by field on both families; the conformance report carries the identity as “ISO 3744:2010 Eq. 23 / clause 3.4 NOTE 1”.
• Status: unreported.

• Location: clause 8.3.4, first sentence and Equation (21) (PDF page 31, printed p. 25).
• The print: “The background noise correction, $K_{1i}$, shall be calculated using Equation (21):” followed by $K_1=-10\lg \left(1-10^{-0,1\Delta L_E}\right)$ dB with $\Delta L_E$ formed from the two means over the measurement surface, $\overline{L_{E(\mathrm{ST})}^{\prime }}$ and $\overline{L_{p(\mathrm{B})}}$.
• The problem: the sentence names a per-position correction and the equation defines a single one from surface means. The twin clause 8.2.3 names $K_1$ in both places and forms it from the same surface means (Equation (16)), and 8.3.5 subtracts the unsubscripted $K_1$ in Equation (22). The subscript is the per-microphone convention of ISO 3741:2010 clauses 9.1.2 and 9.2.2 ($K_{1i}$, Equations (14) and (25)), where each position is corrected before the average, and does not belong to this clause.
• Evidence: Verified on PDF page 31 (printed p. 25) of ISO 3744:2010, against clause 8.2.3 on PDF page 29 (printed p. 23).
• Library behaviour: sound_energy_pressure forms one $K_1$ per band from the surface means, as Equation (21) prints it and as sound_power_pressure does for Equation (16); no per-position correction is applied in the ISO 3744 chain. No change was required.
• Status: unreported.

• Location: Clause 5, Formula (2), the definitions of the symbols of the prominence $P=3{\log }_{10}[r/(\text{dB/s})]+2{\log }_{10}(d/\text{dB})$.
• The print: “r is the onset rate (OR) as defined in 3.4” and “d is the level difference (LD) as defined in 3.5”.
• The problem: the two cross-references are swapped. The document’s own terms and definitions set 3.4 as the level difference LD (“difference in decibels of L_pAF between the level of the end point L_e and the level of the starting point L_s of the onset”) and 3.5 as the onset rate OR (“slope in decibels per second of the straight line that gives the best approximation to the onset”). Read literally, Formula (2) would take three times the logarithm of a level difference plus twice the logarithm of a slope, inverting the weights the method assigns to the two quantities. The spelled-out names in the same list (“the onset rate (OR)”, “the level difference (LD)”) and the units given for each (“dB/s” for $r$, “dB” for $d$) make the intended reading unambiguous.
• Evidence: side-by-side reading of 3.4, 3.5 and the Clause 5 symbol list; the units printed with each symbol contradict the clause numbers printed with them.
• Library behaviour: implements the spelled-out reading, weighting the onset rate by 3 and the level difference by 2 (predicted_prominence in impulsive_sound.py), which is also the NT ACOU 112:2002 form the PAS carries over.
• Status: unreported.

• Location: Annex H (informative), H.4.2.7 “Meteorological and radiation impedance corrections”, the paragraph that sizes $u_{C_1+C_2}$ from the Annex G correction.
• The print: “At 120 m altitude and 23 °C the correction is zero and at 500 m altitude the correction is 0,6 dB. Assuming a triangular distribution for this uncertainty, the standard deviation is $s_{\mathrm{met}}=0,6/\sqrt{6}=0,3\mathrm{dB}$.”
• The problem: two independent defects in one sentence pair. (a) Annex G, which is normative and which this paragraph points at, gives $C_1+C_2=0,394$ dB at 500 m and 23,0 °C, not 0,6 dB. The reading is self-validating: the same two equations give $-4,6\times 10^{-5}$ dB at 120 m and 23,0 °C, which is the “zero” the same sentence prints, so the constants and the temperature terms are being read as the standard intends. 0,6 dB is reached at about 697 m at 23,0 °C, or at 500 m only if the air is at 30,1 °C. (b) $0,6/\sqrt{6}=0,245$, not 0,3. The quotient does not give the result printed beside it: 0,3 dB is exactly $0,6/2$, so either the divisor or the result is wrong. For a triangular distribution of half-width $a$ the standard deviation is $a/\sqrt{6}$, which is the divisor the sentence names.
• Evidence: H.4.2.7 read on PDF page 82 (printed p. 73), against Annex G Equations (G.1) and (G.2) with $a=2,2560\times 10^{-5}$ m${}^{-1}$, $b=5,2553$, ${\theta }_0=314$ K and ${\theta }_1=296$ K on PDF pages 73 and 74 (printed pp. 64 and 65), all of BS EN ISO 3744:2010. Both values were recomputed from the printed equations alone.
• Library behaviour: the Annex H uncertainty budget is not modelled, so no published number depends on either figure. The Annex G correction itself is evaluated from Equations (G.1) and (G.2) by reference_atmosphere_correction, and the conformance check “ISO 3744:2010 Annex G / H.4.2.7” pins the half of the paragraph that is right: the correction vanishes at 120 m and 23 °C.
• Status: unreported.

• Location: Table 2, “Atmospheric attenuation coefficient α for octave bands of noise”, row 15 °C / 80 % relative humidity, column 1 kHz.
• The print: $\alpha =4,1\text{dB/km}$.
• The problem: Table 2 is a rounded extract of ISO 9613-1, to which the clause itself defers (“For values of α at atmospheric conditions not covered in table 2, see ISO 9613-1”). Evaluating the ISO 9613-1 pure-tone formula at 1 kHz, $15{}^{\circ }\text{C}$, $80\%$ RH and $101,325\text{kPa}$ gives $4,1511\text{dB/km}$, which rounds to $4,2$, not the printed $4,1$. The neighbouring cells of the same row round correctly (2 kHz: $8,338$ -> printed $8,3$; 4 kHz: $23,86$ -> $23,7$ at the exact band centre), as do the 1 kHz cells of the other rows ($15{}^{\circ }\text{C}$ / $50\%$: $4,164$ -> printed $4,2$), so the defect is confined to this cell.
• Evidence: independent evaluation of the ISO 9613-1 coefficient at both the nominal and the exact band-centre frequency ($4,1511\text{dB/km}$ either way, 1 kHz being both).
• Library behaviour: unaffected. The library never reads Table 2: it computes $A_{\text{atm}}$ from the ISO 9613-1 formula directly (air_absorption.py), so it yields $4,15\text{dB/km}$ for this condition.
• Status: unreported.

• Location: Table 20, “Single number step by step results” of test case T08, the row naming the middle-region overlap factor $q$.
• The print: q (ISO 9613-2:1996, Table 3, footnote 1).
• The problem: footnote 1 of ISO 9613-2:1996, Table 3 is about which ground factor and which height each outer region takes (“For calculating $A_s$, take $G=G_s$ and $h=h_s$…”). It says nothing about $q$. The factor $q$ is defined by footnote 2 of the same table, which is where the guideline itself sends the reader in the four other places it prints the row: Table 3 (T01), Table 8 (T04), Table 14 (T06) and Table 22 (T09) all read “Table 3 footnote 2”. Table 20 is the single occurrence that reads footnote 1, and the value it carries, $q=0,23$, is the one footnote 2 produces.
• Evidence: the row was read on PDF page 23 (printed p. 17) of ISO/TR 17534-3:2015, and the four consistent occurrences of the same row on PDF pages 13, 16, 20 and 41 (printed pp. 7, 10, 14 and 35) of the same edition; the two footnotes it points at were read on PDF page 10 (printed p. 8) of ISO 9613-2:1996.
• Library behaviour: unaffected. The typographical slip is in a cross-reference, not in a number, and ground_attenuation implements $q$ from footnote 2, which is what reproduces the printed 0,23.

• Location: Section 6.7.3, the symbol list under Equation (36), the entry for the equivalent absorption area A.
• The print: “A äquivalente Absorptionsfläche; in m², Gleichung (36)” / “A is the equivalent absorption area; in m², Equation (36)”.
• The problem: Equation (36) is the level equation the list belongs to, $L_P=L_W+10\lg [Q/(4\pi r^2)+4/A]$, in which A is an input. It does not define A. The guideline defines it twice further down the same section: Equation (37), $A=0,163V/T$, and Equation (39), $A=\sum {\alpha }_i{S}_n+\sum A_n$. The reference is a self-reference, and it stands in both language columns, so it is a typesetting slip in the original rather than a translation one.
• Evidence: verified on PDF page 43 (printed p. 43) of VDI 2081 Blatt 1:2001-07, with Equations (37) and (39) on PDF pages 44 and 44 (printed pp. 44 and 44) of the same print.
• Library behaviour: unaffected. The slip is in a cross-reference, not in a number; room_effect takes A as an argument and sabine_absorption_area implements Equation (37).
• Status: unreported.

• Location: Section 6.7.3, the sentence stating where the reverberation field begins, immediately after Equation (36b).
• The print: German, “Der Nachhallbereich beginnt bei halbkugelförmiger Schallausbreitung in einer Entfernung, die größer ist als $r_H=0,2\sqrt{A}$”; English, “The reverberation area begins as a spherical sound propagation at a distance which is greater than $r_H=0.2\sqrt{A}$”.
• The problem: halbkugelförmig is hemispherical, not spherical, and the printed constant sides with the German. The reverberation radius is $r_H=\sqrt{QA/16\pi }$, which is $0,199\sqrt{A}$ at the $Q=2$ of a half space and $0,141\sqrt{A}$ at the $Q=1$ of a full one. Only the first rounds to the printed $0,2$. A reader following the English column would take $0,2\sqrt{A}$ for the spherical radius and place the reverberation field 41 % too far out.
• Evidence: verified on PDF page 44 (printed p. 44) of VDI 2081 Blatt 1:2001-07, both columns of the same sentence read side by side.
• Library behaviour: unaffected. critical_distance takes Q as an argument and states the hemispherical reading in its own text.
• Status: unreported.

Not verified against the page. ANSI S3.5-1997 is not held locally (the R package SII vignette is held, not the standard), so what this entry calls “the print” is the working group’s own description of it, not a page this project has read. The recomputations below are independent and do reproduce, but the printed characters rest on the errata list alone. The standard is on the maintainer’s pending-acquisition list; when a copy arrives the entry is to be re-verified against the print of printed pp. 21-22 and this notice removed.

• Location: Annex C, Table C.1 (octave-band worked example, p. 21) and Table C.2 (one-third-octave worked example, p. 22) of the 1997 printing.
• The print (per the working group’s errata): (a) Table C.1, row $i=5$, the level-distortion factor $L_i$ under Step 6 is printed as $0.10$; (b) Table C.2, first row, the self-speech-masking slope $C_i$ is printed as $-45.59$.
• The problem: both cells contradict the standard’s own normative formulas. (a) Clause 5.7 with the example’s inputs ($E_5^{\prime }=20\text{dB}$, $U_5=9.33\text{dB}$) gives $L_5=1-(20-9.33-10)/160=0.9958$, which prints to two decimals as $1.00$, not $0.10$. (b) Clause 5.4 with the example’s inputs ($B_1=40\text{dB}$, $f_1=160\text{Hz}$) gives $C_1=-80+0.6(40+10{\log }_{10}160-6.353)=-46.587$, which prints as $-46.59$, not $-45.59$; the example’s $Z_i$ column is only consistent with the corrected slope ($Z_2$ recomputes to $34.658$ = printed 34.66 dB, whereas the misprinted slope would give 34.76 dB). The Table C.1 example is the octave-band procedure and the Table C.2 example the one-third-octave procedure, so one cell of each is affected.
• Evidence: the official errata list published by ASA Working Group S3-79, the committee that maintains ANSI S3.5, on its support site (sii.to): “Page 21, Table C1, row i=5, column Li under Step 6: the value printed as 0.10 should be changed to 1.00” and “Page 22, Table C2, the first row of numbers, value −45.59 should be −46.59”; plus independent recomputation of both cells from the normative clauses (above). The same list carries five further corrections (a reference spelling, the Tables 1-4 caption wording recorded in the next entry, the insertion gain $G_i$ missing from Eq. 23, and two Annex B fixes, a cross-reference “B16” that should read “B15” and a wording change about the audio-visual approximation); none of those touches a formula this library implements. The source is the WG S3-79 errata list at sii.to/html/errata.html (captured 2026-07-30, re-checked live 2026-08-04). It is not the printed page and cannot substitute for it, which is why this entry carries the notice above.
• Library behaviour: unaffected; the library computes the corrected values from the normative clauses and always did. Its Annex C.2 anchors (tests/reference_data/, ANSIS3_5_ANNEX_C1* and ANSIS3_5_ANNEX_C2*) pin the errata-consistent chain of both examples, cross-checked to double precision against the working group’s own reference implementation SII.C and its published test-case results. The Table C.1 cell is pinned directly: the level-distortion factor of clause 5.7 for row $i=5$ of the Annex C.1 octave-band example computes to $0.99581$, which prints as the corrected $1.00$.
• Status: published corrections by the issuing working group; nothing to report upstream.

Not verified against the page. As with the entry above, ANSI S3.5-1997 is not held locally, so the wording of the four captions is taken from the working group’s errata list rather than from a page this project has read. The argument that the tables carry no threshold column is independent and does hold against the transcribed constants. Re-verify against the print of printed pp. 3-5 when the standard is acquired.

• Location: the captions of Tables 1, 2, 3 and 4 (pp. 3-5 of the 1997 printing), the constant tables of the four band procedures: critical band (21 bands), equally-contributing critical band (17 bands), one-third octave (18 bands) and octave (6 bands).
• The print (per the working group’s errata): each caption lists the quantities the table tabulates and includes the phrase “hearing threshold levels,”.
• The problem: none of the four tables tabulates a hearing threshold level. Each carries the band centre frequency (and, for Tables 1, 2 and 4, the band limits), the band-importance function $I_i$, the standard speech spectrum level $U_i$ by vocal effort and the reference internal noise spectrum level $X_i$. The hearing threshold level $T_i^{\prime }$ is a user input to the procedure (clause 5.5, where the equivalent internal noise spectrum level is $X_i^{\prime }=X_i+T_i^{\prime }$), which is exactly the quantity the caption invites the reader to look for in the table and to confuse with $X_i$.
• Evidence: the official errata list published by ASA Working Group S3-79, the committee that maintains ANSI S3.5, on its support site (sii.to): “Pages 3-5, Tables 1-4: In each of the figure captions the phrase ‘hearing threshold levels,’ should be deleted” (the WG S3-79 errata list at sii.to/html/errata.html, captured 2026-07-30, re-checked live 2026-08-04; an earlier revision of this entry dropped the word “figure” from the quotation); plus the tables themselves, which have no such column.
• Library behaviour: unaffected. The four tables are implemented with the columns they actually carry, exposed per procedure by sii_procedure() as band_importance, speech_spectrum ($U_i$) and internal_noise ($X_i$), and the hearing threshold stays the threshold= argument of speech_intelligibility_index (src/phonometry/speech/sii.py).
• Status: published correction by the issuing working group; nothing to report upstream.

• Location: section A.4.2, Eq. (27) (atmospheric absorption coefficient) and the sentence defining its symbols, printed p. 21.
• The print: Eq. (27) pairs the coefficient $6.6928\cdot 10^{-6}$ with $f_{rO}$ and $1.3415\cdot 10^{-6}$ with $f_{rN}$, and the sentence below reads “the variables f_rN = 75692 Hz and f_rO = 630.7 Hz represent the vibrational relaxation frequencies of oxygen and nitrogen respectively”.
• The problem: the two subscripts are swapped in the definition sentence. The values match the names it gives them (75 692 Hz is the oxygen relaxation frequency and 630.7 Hz the nitrogen one at the reference conditions), but they are assigned to the opposite symbols, so the equation as printed multiplies the oxygen coefficient by the nitrogen relaxation frequency and vice versa. Evaluated that way it gives 14.2 dB/km at 500 Hz against the guidance’s own Table 4 value of 3.1 dB/km; with $f_{rO}$ and $f_{rN}$ exchanged it gives 3.07 dB/km, reproducing Table 4 and the ISO 9613-1 pure-tone coefficient to 0.02 dB/km. An earlier revision of this entry quoted the printed value as 14.3 dB/km and framed the defect as a wrong pairing of the coefficients rather than as swapped subscripts in the definition.
• Evidence: numeric evaluation of Eq. (27) with the printed assignment and with the assignment exchanged, against the Table 4 500 Hz cell on the same page. Verified on PDF page 20 (printed p. 21) of NORAH2 SC01.D1.5d (EASA.2020.FC.06):2024.
• Library behaviour: implements the correct pairing; the module docstring carries a defensive note so the misprint is not transcribed as a “fix”.
• Status: unreported.

• Location: section A.3.3, Eq. (21) (flight path angle).
• The print: $\gamma =\text{acos}(\Delta Z/\Delta S)$.
• The problem: the arccosine of the climb-to-path ratio returns the complement of the path angle ($90^{\circ }$ in level flight, where $\gamma$ must be $0^{\circ }$) and contradicts the guidance’s own use of $\gamma$ as the climb/descent angle throughout section A.3. ECAC Doc 32, 1st ed., Eq. (10) prints the correct form, $\gamma =\text{atan}(\Delta Z/\Delta S)$ with the horizontal $\Delta S$ of its Eq. (8).
• Evidence: evaluation in level flight; cross-check against Doc 32 Eq. (10) and against the NORAH2 prototype input files, whose Vang columns are climb/descent angles ($0^{\circ }$ in level segments).
• Library behaviour: flight_path_kinematics implements the Doc 32 atan form; the result docstring carries the defensive note.
• Status: unreported.

• Location: section A.3.1, steps 2 to 4 (flight-condition interpolation), against the triangulation lookup tables shipped with the NORAH2 database (*_triangulation.int).
• The print: steps 2 and 3 normalise the database conditions (spans, with $F_{fc}=2$ on the path angle) and step 4 computes “the Delaunay triangulation for the database flight conditions γ̄_j and V̄_j”, i.e. of the normalised points, offering a lookup table as an equivalent.
• The problem: the lookup tables shipped with the database (which the guidance says are part of the hemisphere data and should not be edited) are the Delaunay triangulation of the raw $(V,\gamma )$ conditions, not of the normalised ones: for the R22 set, 14 of the 27 shipped triangles differ from the Delaunay triangulation of the normalised conditions. A Delaunay triangulation is not invariant under the anisotropic normalisation, so the two prescriptions select different enveloping triangles for part of the envelope. The distance weights of Eq. (7)/(8) do use the normalised coordinates in the prototype (verified against its blended outputs).
• Evidence: recomputation of both triangulations for the R22 database; bin-for-bin reproduction of the prototype’s per-step hemisphere selection with the shipped tables, and of its blended levels with normalised-space weights, to 0.05 dB.
• Library behaviour: flight_condition_weights follows the printed method (Delaunay of the normalised conditions) by default and accepts the database lookup table via triangles, which reproduces the reference implementation exactly.
• Status: unreported.

• Location: section A.4.5, Eq. (46) (source-side ground effect weighted by diffraction).
• The print: the weighting exponent reads $(\Delta L_{g,s^{\prime }}-\Delta L_{d,s})/20$.
• The problem: no term $\Delta L_{g,s^{\prime }}$ exists; the prose directly below the equation defines $\Delta L_{d,s^{\prime }}$ as “the attenuation due to the diffraction between the image source S′ and R”, the receiver-side companion Eq. (47) prints the parallel term correctly as $\Delta L_{d,r^{\prime }}$, and the CNOSSOS-EU method the section is based on writes ${\Delta }_{\text{ground}}(S,O)$ with ${\Delta }_{\text{dif}}(S^{\prime },R)$ in that position. The subscript $g$ is a misprint for $d$.
• Evidence: internal consistency of the section (its own prose and Eq. (47)) and the CNOSSOS-EU source of the equations.
• Library behaviour: implements the image-source diffraction term $\Delta L_{d,s^{\prime }}$ as defined by the prose.
• Status: unreported.

• Location: section A.4.5, the definitions under Eq. (46) (printed p. 32) and Eq. (47) (printed p. 33).
• The print: four cross-references to eq. 44, in three different wordings: “calculated as per eq. 44” for $\Delta L_{d,s^{\prime }}$ and again for $\Delta L_{d,s}$ under Eq. (46); “calculated as in eq. 44” for $\Delta L_{d,r^{\prime }}$ under Eq. (47); and “calculated as in Subsection eq. 44” for $\Delta L_{d,s}$ under Eq. (47). An earlier revision of this entry quoted all four with the first wording.
• The problem: Eq. (44) is the multiple-diffraction coefficient $C^{\prime \prime }$; the attenuation due to diffraction is Eq. (42). All four cross-references point at the auxiliary coefficient instead of the formula they describe, and the fourth also carries a dangling “Subsection” with no subsection number after it.
• Evidence: the terms are attenuations in dB, which only Eq. (42) produces; Eq. (44) is a dimensionless coefficient consumed by Eq. (42). Verified on PDF pages 31 and 32 (printed pp. 32 and 33) of NORAH2 SC01.D1.5d (EASA.2020.FC.06):2024.
• Library behaviour: evaluates the image-path and direct diffraction terms with Eq. (42), using Eq. (44) for $C^{\prime \prime }$ inside it.
• Status: unreported.

• Location: section A.3.5, Approach 3, step 3 (printed p. 18), against the “Fl. idle” row of Table 3 (printed pp. 18-19).
• The print: the step reads “add offset of 12 dB* to derive out of ground hover from the in-ground hover disk, -12 dB* to derive reduced-rpm idle from in-ground hover disk, and -2.5 dB* to derive full-rpm idle from out of ground hover”; the table prints $L{A}_{FL.idle}(\theta )=L{A}_{\mathrm{HIGE}}(\theta )-2.5{\mathrm{dB}}^{\ast }$.
• The problem: the prose derives full-rpm idle from out-of-ground hover where the table derives it from in-ground hover, and the two prescriptions land 12 dB apart (via the prose, $L{A}_{\mathrm{HOGE}}(\theta )-2.5=L{A}_{\mathrm{HIGE}}(\theta )+9.5$; via the table, $L{A}_{\mathrm{HIGE}}(\theta )-2.5$). Only the table keeps the physical ordering of the conditions (full-rpm idle above reduced-rpm idle, both below in-ground hover). The paragraph that introduces these phases, at the end of section A.3.3 (printed p. 17), is itself left unfinished (“For specific phases of a flight such as, turns, hover, taxiing”), pointing at an editing pass the section did not get.
• Evidence: the corrections shipped with the V2.0.74 public database are all relative to the in-ground-hover disk (Fullrpmidle -2 in every type’s interpolation lookup file), agreeing with the table and not with the prose. Verified on PDF pages 16, 17 and 18 (printed pp. 17, 18 and 19) of NORAH2 SC01.D1.5d (EASA.2020.FC.06):2024.
• Library behaviour: hover_derived_hemisphere applies every Table 3 offset from the in-ground-hover hemisphere, as the table prints; the docstring states the base condition explicitly.
• Status: unreported.

• Location: section A.3.5, last paragraph (printed p. 19).
• The print: “To include taxiing for helicopters with and without wheels into the noise calculation the measured and derived hemispheres for in-ground hover and full-rpm idle respectively should be employed.”
• The problem: read literally, the “respectively” pairs the wheeled helicopter with the in-ground-hover source and the wheel-less one with full-rpm idle, which is the reverse of the operations it models: a helicopter without wheels can only taxi by hovering in ground effect, and a wheeled helicopter ground-taxis on its wheels with the rotor at governed idle, not producing lift. The two lists read as transposed. No oracle settles it (the public release ships no taxi verification case), so the pairing is corrected from the physics of the operations alone.
• Evidence: internal comparison of the two prose lists against the operations they name. Verified on PDF page 18 (printed p. 19) of NORAH2 SC01.D1.5d (EASA.2020.FC.06):2024.
• Library behaviour: no function is affected (the rule selects between two hemispheres the reader has already built); the rotorcraft guide documents the physical pairing, wheel-less taxi on the in-ground-hover hemisphere and wheeled taxi on the full-rpm-idle one, with this caveat.
• Status: unreported.

• Location: Table 3, Approach 3 column (printed pp. 18-19), against the &CORRECTIONS block of the interpolation lookup files shipped with the NORAH2 V2.0.74 public release.
• The print: offsets of +12 dB* (out-of-ground hover), -12 dB* (reduced-rpm idle) and -2.5 dB* (full-rpm idle) from the in-ground-hover disk, with the asterisked note that they were derived from measurements with inverted microphones on ground plates and “may not be valid for other microphone setups”.
• The problem: the reference database the guidance builds on ships different values: every one of the eleven per-type triangulation lookup files (*_triangulation.int) of the public release carries Corr_dB 8, -10 and -2 for the same three operations, so the published constants and the database disagree by 4, 2 and 0.5 dB. The guidance, whose section A.3.1 declares the shipped lookup data part of the hemisphere database and not to be edited, does not mention the difference, and its note questions the validity of the published values without naming the ones actually shipped.
• Evidence: the identical &CORRECTIONS blocks of the eleven triangulation lookup files (*_triangulation.int) of the V2.0.74 public release; the published constants verified on PDF pages 17 and 18 (printed pp. 18 and 19) of NORAH2 SC01.D1.5d (EASA.2020.FC.06):2024.
• Library behaviour: hover_derived_hemisphere defaults to the published Table 3 constants and accepts a measured or database correction as offset_db; the end-to-end hover verification case passes the database’s +8 dB explicitly, and the docstring records the divergence.
• Status: unreported.

• Location: Table 2 (representative ship source levels).
• The print: two cells deviate from the report’s own Eqs. (2) to (5) evaluated with the Table 1 average lengths and speeds: the Merchant value at 25 Hz (about 3 dB high) and the Tanker value at 300 Hz (about 1 dB low). The Fishing Vessel row is not reproducible from the Table 1 averages at all (a constant offset of about 3.8 dB suggests different assumed inputs).
• The problem: the report does not state the exact inputs used for Table 2, and two cells contradict its own equations while every Large Tanker and Super Tanker cell agrees to 0.06 dB.
• Evidence: recomputation of all 25 cells from Eqs. (2) to (5).
• Library behaviour: the regression test pins the reproducible rows and excludes the contradicting cells with the rationale in the test.
• Status: unreported (technical report rather than a standard).

• Location: Eq. (3), the critical-band-rate (Bark) transformation of the excitation-pattern front-end.
• The print: $z(f)=13\cdot \arctan (0.76\cdot 10^{-4}\cdot f)+3.5\cdot \arctan ((f/7500{)}^2)$.
• The problem: the first coefficient is the Zwicker-Terhardt $0.76\cdot 10^{-3}$ with the exponent misprinted. The paper’s own anchors disprove the print: it states $0.5\text{Bark}=50\text{Hz}$ and $23.5\text{Bark}=13.2\text{kHz}$ (section 2.1.2) and $15\text{Bark}=2.7\text{kHz}$ (section 3.1), all of which require $10^{-3}$. With $10^{-4}$, $z(1\text{kHz})=1.05$ instead of $8.51\text{Bark}$ and the model’s 47 filter centres would span 491 Hz to 20 kHz instead of 50 Hz to 13.2 kHz.
• Evidence: evaluation of Eq. (3) under both exponents against the paper’s printed Bark/frequency anchors. The printed section 2.1.2 range “0.5 Bark (50 Hz) to 23.5 Bark (13.2 kHz)” and the section 3.1 anchor “15 Bark (2.7 kHz)” all reproduce under the Zwicker-Terhardt $0.76\cdot 10^{-3}$ (50.6 Hz, 13.07 kHz and 2.71 kHz) and none of them under the printed exponent. Verified on PDF page 4 (printed p. 4) of Osses, García & Kohlrausch, ICA:2016, with the anchors on PDF page 7 (printed p. 7) of the same paper.
• Library behaviour: implements $0.76\cdot 10^{-3}$ with a note at the formula; the carrier-frequency sweep test would catch a regression to the printed value (fluctuation_strength.py).
• Status: unreported (conference paper rather than a standard).

• Location: the Francois-Garrison boric-acid term as transcribed by the textbook, Eq. (3.4.30), printed p. 110. An earlier revision of this entry cited Eq. 3.4.29, which is the total-absorption sum of the three terms on printed p. 109; the boric-acid block is the equation after it.
• The print: $A_1=(8.68/c)\cdot 10^{0.78\text{pH}-5}{\text{dB km}}^{-1}{\text{kHz}}^{-1}$.
• The problem: the original paper (Francois & Garrison 1982, JASA 72, Part II, Eq. (10) and Fig. 7) prints 8.86; the digits are transposed. Only 8.86 reproduces the paper’s own Table IV: with 8.68 the boric-dominated cells at $0.6$ to 30 kHz sit up to $1.7\%$ below the printed totals (worst relative case 2 kHz, 10 °C, $S=35$: $0.1209$ vs the printed 0.123 dB/km).
• Evidence: recomputation of all sampled Table IV cells under both coefficients against the paper’s printed values. Verified on PDF page 131 (printed p. 110) of Medwin & Clay, Fundamentals of Acoustical Oceanography (1998), and on PDF pages 8 and 9 (printed pp. 1886 and 1887) of Francois & Garrison (1982), JASA 72, Part II, which print the paper’s own $A_1=(8.86/c)\cdot 10^{0.78\text{pH}-5}$.
• Library behaviour: implements the paper’s 8.86 with a defensive note; the pinned Table IV set includes the boric-dominated rows.
• Status: unreported (textbook rather than a standard).

• Location: the same Eq. (3.4.30) block, printed p. 110, its last line.
• The print: $q=1412+3.21T+1.19S+0.0167z\text{m/s}$.
• The problem: the quantity the block needs is the sound speed $c$, which is what the two lines above it divide by ($A_1=8.68/c$, and $A_2=21.44S/c$ in the magnesium-sulfate block on the same page). No symbol $q$ is defined anywhere in the section, so the transcribed system is not closed: a reader following the printed symbols has no value for $c$. Francois & Garrison 1982 Part II prints the same polynomial as $c=1412+3.21T+1.19S+0.0167D$, introduced by “where c is the sound speed (m/s), given approximately by”.
• Evidence: the block’s own use of $c$ two lines above, and the source paper. Verified on PDF page 131 (printed p. 110) and PDF page 130 (printed p. 109) of Medwin & Clay (1998), and of PDF page 8 (printed p. 1886) of Francois & Garrison 1982 Part II (JASA 72).
• Library behaviour: unaffected; the absorption model takes the sound speed from the same polynomial under the name c.
• Status: unreported (textbook rather than a standard).

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• Location: Eq. (5b), the mass-reactance coefficient of the microperforated panel, printed as $k_m=1+[1+k^2/2{]}^{-1/2}+0.85d/t$.
• The print: the first bracket term reads $(1+k^2/2{)}^{-1/2}$.
• The problem: the same paper’s Eq. (4), from which (5b) is factored, prints the term as $(3^2+k^2/2{)}^{-1/2}$, and only that form reproduces the Crandall low-$k$ limit $Z_1\to (4/3)j\omega {\rho }_{0}t$ of the paper’s own Eq. (3a): at $k\to 0$ the printed (5b) gives an internal mass factor of 2 instead of 4/3. The paper’s own Fig. 1 confirms it: with $0.85\cdot d/t=0.85$ the plotted $k_m$ starts near $2.2$ ($=4/3+0.85$) at $k=0.1$, not at $2.85$.
• Evidence: recomputation of both bracket variants against Eq. (4), Eq. (3a) and the Fig. 1 curve; the exact Bessel solution of Eq. (2) agrees with Eq. (4) within Maa’s stated $\sim 6\%$ only with the $3^2$ form (the 1 form errs by $>30\%$ at low $k$). Verified on PDF page 2 (printed p. 2862) of Maa (1998), “Potential of microperforated panel absorber”, JASA 104(5), which carries Eq. (4) and Eq. (5b) fifteen lines apart on the same column.
• Library behaviour: implements the exact Eq. (2) (no approximation), so the misprint does not enter the code; the regression test test_maa_exact_vs_wide_range_approximation pins the exact solution to the corrected Eq. (4) form.
• Status: unreported (journal paper; the correct form appears in Maa’s earlier 1975/1987 papers and in secondary literature).

• Location: Eqs. (7) and (8), the rectangular-duct visco-thermal effective density and bulk modulus (Stinson’s series, used for the square necks and cavities of the slit + Helmholtz-resonator absorber).
• The print: the leading normalising constant of both series is 4: ${\rho }_{\text{eff}}=-{\rho }_0\cdot a^2{b}^2/(4\cdot G_{\rho }^2\cdot \Sigma )$ and the matching $4\cdot (\gamma -1)\cdot G_{\kappa }^2/(a^2{b}^2)$ factor inside ${\kappa }_{\text{eff}}$.
• The problem: the correct constant is 64 (a factor-16 error). Only 64 reproduces the exact limits of the model: as the boundary layers vanish ${\rho }_{\text{eff}}\to {\rho }_0$ and ${\kappa }_{\text{eff}}\to {\kappa }_0$ (the printed 4 gives $16\cdot {\rho }_0$), and at DC the square duct’s $j\omega \cdot {\rho }_{\text{eff}}$ tends to the exact Shah-London Poiseuille flow resistivity: the series value $a^6/(64\cdot S_0)=28.4542$ matches $fRe/2=28.455$ (in units of $\eta /a^2$), where $S_0$ is the double transverse-mode sum at $G=0$; the printed 4 gives sixteen times that.
• Evidence: evaluation of both constants against the boundary-layer-free limits and the Shah-London exact square-duct value; the wide-duct limit of the series also only matches the papers’ own slit model (Eq. (6)) with 64.
• Library behaviour: implements 64 with a docstring note; the limits are pinned in tests/materials/absorbers/test_slow_sound.py and the conformance check “Poiseuille limit (Stinson 1991)”.
• Status: unreported (journal paper rather than a standard).

• Location: Appl. Sci. Eq. (3), the characteristic radiation impedance of the slits, and the identical Methods reprint in the metadiffusers paper (Sci. Rep. 7, 5389, Eq. (5)).
• The print: $Z_{\Delta l_{\text{slit}}}=-i\omega \cdot \Delta l_{\text{slit}}\cdot {\rho }_0/(\varphi t\cdot S_0)$.
• The problem: the term models the added radiation mass of the slit mouth, but the printed $-i\omega$ prefactor is an opposite-time-convention ($e^{-i\omega t}$) expression inconsistent with the papers’ otherwise $e^{+i\omega t}$ transfer-matrix chain (the $+i$ off-diagonal slit matrices of Appl. Sci. Eq. (2) and the $-i$ cotangent-type resonator impedance). Transcribed literally into that chain, the correction raises the slit-panel resonance where an added mass must lower it: for a 1 mm slit with a 30 mm lattice step and 50 mm period the absorption peak moves from 378.6 Hz to 386.8 Hz as printed, against 370.8 Hz with the mass sign. The neck end corrections of the same model behave correctly (they lower the resonator resonance).
• Evidence: numerical evaluation of both signs of the correction against the uncorrected panel; the direction of the neck end corrections of the same papers as the consistent control.
• Library behaviour: uses the added-mass sign ($+j\omega$ in the $e^{+j\omega t}$ convention of the library), conjugating the printed term exactly as it conjugates the papers’ Stinson duct series; direction and peak are pinned by test_slit_radiation_correction_lowers_resonance in tests/materials/absorbers/test_slow_sound.py.
• Status: unreported (journal papers rather than standards).

• Location: Table 5.1, “Coefficient and exponent values in the Delany and Bazley, Miki and modified Miki models”, row “Miki [6,7]”, coefficient $r$.
• The print: $r=0.0109$.
• The problem: the original source (Miki 1990, J. Acoust. Soc. Jpn (E) 11(1), Eq. (34)) prints $\beta (f)=(\omega /c_0)[1+0.109\cdot (f/\sigma {)}^{-0.618}]$; the table drops a digit. With 0.0109 the real part of the Miki wavenumber at $f/\sigma =0.01$ is $1.19$ instead of $2.88$, inconsistent with the same table’s Delany-Bazley row ($3.10$ from its own $r=0.0862$, $s=-0.693$) and with the “modified Miki” row the book itself derives from it.
• Evidence: digit check against the original Miki (1990) paper (Eqs. (30)–(34)) and cross-computation of both variants at the fit-range edge. Verified on PDF page 168 (printed p. 149) of Attenborough & Van Renterghem, Predicting Outdoor Sound 2e:2021, and on PDF page 4 (printed p. 22) of Miki, J. Acoust. Soc. Jpn (E) 11(1):1990.
• Library behaviour: implements Miki’s original 0.109; the digitization point $f/\sigma =0.1$ is pinned in tests/reference_data/ and in the conformance check “Miki 1990 Eqs. (30)-(34)”.
• Status: unreported (textbook rather than a standard).

• Location: Eq. (5.13), the Johnson-Champoux-Allard bulk complex density, with $G(\Lambda )=\sqrt{1-4iT\eta {\rho }_0\omega /(R_S^2{\Lambda }^2{\Omega }^2)}$.
• The print: the tortuosity $T$ appears to the first power inside $G(\Lambda )$.
• The problem: Johnson et al. (1987) and the standard JCA formulation (Cox & D’Antonio 3e Eq. (6.19); Allard & Atalla) carry $T^2={\alpha }_{\infty }^2$ there. The first-power print breaks the high-frequency asymptote that defines the viscous characteristic length: with $T^2$ the density tends to $(T{\rho }_0/\Omega )(1+(1-j){\delta }_v/\Lambda )$ with ${\delta }_v=\sqrt{2\eta /{\rho }_0\omega }$, while the printed form tends to a ${\delta }_v/(\Lambda \sqrt{T})$ correction, which for $T=2$ means an error of $29\%$ in the boundary-layer term for the same $\Lambda$.
• Evidence: asymptotic expansion of both variants against the Johnson et al. definition of $\Lambda$ and against Cox & D’Antonio Eq. (6.19); the library’s high-frequency JCA test pins the $T^2$ behaviour. Verified on PDF page 173 (printed p. 154) of Predicting Outdoor Sound 2e:2021.
• Library behaviour: implements the standard $T^2$ form (Cox & D’Antonio Eq. (6.19)); the asymptote is pinned in test_high_frequency_density_asymptote.
• Status: unreported (textbook rather than a standard).

• Location: Section 8.9.1, Eq. (8.141) (printed p. 461), the transmission loss of a muffler from the elements of its total four-pole matrix.
• The print: $$TL=10\lg \left[{\left(\frac{1+M_n}{1+M_1}\right)}^2\cdot \frac{1}{4}\cdot {\left|\frac{Z_{A1}}{Z_{An}}{T}_{11}+\frac{T_{12}}{Z_{An}}+Z_{A1}{T}_{21}+\frac{Z_{An}}{Z_{A1}}{T}_{22}\right|}^2\right],$$ i.e. with the impedance ratio $Z_{A1}/Z_{An}$ weighting $T_{11}$ and its inverse weighting $T_{22}$.
• The problem: the source the equation itself cites (Munjal, Acoustics of Ducts and Mufflers 2e, Eq. (3.27), p. 105) carries the overall prefactor $Z_{An}/Z_{A1}$ (equivalently $\sqrt{S_1/S_n}$ inside a $20{\log }_{10}$ form) with $T_{11}$ unweighted and $Z_{A1}/Z_{An}$ on $T_{22}$. As printed, Eq. (8.141) fails the sudden-expansion limit: a zero-length element ($T=I$) between $S_1=0.01{\text{m}}^2$ and $S_n=0.02{\text{m}}^2$ is a sudden area expansion with the classic $TL=10{\log }_{10}[(1+m{)}^2/(4m)]=0.512\text{dB}$ ($m=S_n/S_1=2$), but the printed equation gives $\frac{1}{4}\cdot (Z_{A1}/Z_{An}+Z_{An}/Z_{A1}{)}^2=1.938\text{dB}$. Reading the ratios as an overall $Z_{A1}/Z_{An}$ prefactor instead is also wrong: it gives 6.532 dB on the same oracle and violates reciprocity ($11.34$ vs -0.70 dB for an expansion chamber between unequal pipes; a negative TL for a passive element). The misprint is invisible whenever the inlet and outlet areas are equal, where every variant reduces to Eq. (8.148).
• Evidence: numeric evaluation of the zero-length identity element and of an unequal-port expansion chamber under the printed form, the inverted prefactor and Munjal Eq. (3.27); only Munjal’s form reproduces the sudden-expansion classic (0.512 dB, both directions) and is reciprocal.
• Library behaviour: transmission_loss in silencers.py implements Munjal Eq. (3.27), with the sudden-expansion limit and TL reciprocity pinned by regression tests (tests/noise_control/test_silencers.py) and a defensive note at the formula.
• Status: unreported (textbook rather than a standard).

• Location: Chapter 18, “Multiple Open Microphones”, Eq. (18.24) (printed p. 699), the gain-before-feedback stability criterion generalised to several open microphones.
• The print: $Z_S+L_{H-M}+\Delta L_{\text{nom}}\le L_{H-L}+D_M(\theta )-10$, with the microphone directivity index entering the right-hand side with a plus sign.
• The problem: Eq. (18.24) is the number-of-open-microphones generalisation of Eq. (18.20) (printed p. 698), which reads $Z_S+L_{H-M}\le L_{H-L}-D_M(\theta )-10$ and which follows in turn from the oscillation condition Eq. (18.19), $Z_S+L_{H-M}=L_{H-L}-D_M(\theta )$, obtained by substituting the feedback-loop gain $G_S=L_{H-M}-L_{H-L}+D_M(\theta )$ (Eq. (18.18)) into $Z_S+G_S=0$ (Eq. (18.16)). Setting $N_m=1$ makes $\Delta L_{\text{nom}}=0$, so Eq. (18.24) must reduce to Eq. (18.20) and does not. The sign matters physically: $D_M(\theta )$ is “usually negative” in Long’s own definition (about $-2$ to -3 dB for a cardioid pointed at the talker), so as printed a directional microphone would cost gain before feedback instead of buying it, inverting the chapter’s own conclusion that “it is prudent to incorporate a cardioid or hypercardioid microphone into a system”.
• Evidence: the printed equation reads $Z_S+L_{H-M}+\Delta L_{\text{nom}}\le L_{H-L}+D_M(\theta )-10$, against $Z_S+L_{H-M}\le L_{H-L}-D_M(\theta )-10$ two pages earlier, where the same position holds a minus. (An earlier revision of this entry quoted the pdftotext extraction, Z S þ L HM þ DL nom L HL þ D M ðqÞ 10, in which þ is the ligature this PDF uses for ”+” and every minus sign has been dropped entirely; that extraction cannot distinguish a plus from a minus and should never have been the evidence.) Verified on PDF page 697 (printed p. 699) and PDF page 696 (printed p. 698) of Long, Architectural Acoustics 2e (2014). The minus sign is the one that reproduces Long’s own worked special cases at $N_m=1$: with $Z_S=-6\text{dB}$, Eq. (18.21) gives $L_{H-M}\le L_{H-L}-D_M(\theta )-4$ (an omnidirectional microphone 4 dB below the average audience level), and Eq. (18.22) gives $L_{H-M}\le L_{H-L}-2$ for a cardioid at $D_M=-2\text{dB}$. Neither special case is recoverable from the printed Eq. (18.24).
• Library behaviour: feedback_stability in sound_reinforcement.py implements the sign of Eq. (18.20), with a note at the criterion. Both of Long’s special cases are pinned by regression tests (tests/electroacoustics/test_sound_reinforcement.py) and by the conformance checks “Long, Architectural Acoustics 2e, Eq. (18.21)” and “Eq. (18.22)”.
• Status: unreported (textbook rather than a standard, so non-normative).

• Location: Chapter 17, “Restaurant Design”, Eq. (17.53) (printed p. 666), the minimum absorption per occupied table for adequate cross-table communication.
• The print: $A_{\text{tab}}>6.33r_s^2$.
• The problem: the bound is Eq. (17.52), $L_{\text{SN}}=10{\log }_{10}[Q/(4\pi r^2)]+10{\log }_{10}[A_{\text{tab}}/4]$, solved for $A_{\text{tab}}$ at the stated threshold $L_{\text{SN}}>-6\text{dB}$, which gives $A_{\text{tab}}>16\pi \cdot 10^{-0.6}{r}_s^2/Q$. With the $Q=2$ the chapter uses for a talker, that constant is 6.3130, not 6.33. The gap is $0.27\%$, i.e. the last printed digit: 6.33 is what $16\pi \cdot 10^{-0.6}/2$ returns if $10^{-0.6}$ is carried coarsely as 0.252 instead of 0.251 19. This is graded as a rounding-level discrepancy rather than a structural error of the formula, since the formula itself is confirmed by its companion (below) and no consistent alternative assumption reproduces 6.33 (it would require $Q=1.995$).
• Evidence: the immediately following Eq. (17.54) is the same closed form at the privacy threshold $L_{\text{SN}}<-9\text{dB}$, and its printed constant 3.16 is exactly what $16\pi \cdot 10^{-0.9}/2=3.1640$ gives, confirming both the formula and $Q=2$. Only the -6 dB constant is off. What does not discriminate is Long’s prose one paragraph later, “at least 6.3 or more square meters (68 sq ft) of absorption per table”: 6.313 m² is $67.95{\text{ft}}^2$ and 6.33 m² is $68.14{\text{ft}}^2$, so both print as 68 sq ft, and both round to 6.3 m². An earlier revision of this entry offered that conversion as corroboration. Verified on PDF page 665 (printed p. 666) of Long, Architectural Acoustics 2e (2014).
• Library behaviour: absorption_per_table in crowd_noise.py computes the bound from Eq. (17.52) rather than hardcoding either constant, so both bounds stay mutually consistent; the 6.313 value and the printed 3.16 are pinned by regression tests (tests/room/test_crowd_noise.py) and the 3.16 constant by the conformance check “Long, Architectural Acoustics 2e, Eq. (17.54)”.
• Status: unreported (textbook rather than a standard, so non-normative); graded as a rounding discrepancy rather than a structural defect.

• Location: Chapter 14, Table 14.7, “Insertion Loss of Round Elbows” (printed p. 541), indexed by the frequency-width product $fw$ (kHz times inches).
• The print: four rows only: $fw<1.9$ → 0 dB; $1.9<fw<3.8$ → 1 dB; $3.8<fw<7.5$ → 2 dB; $fw>15$ → 3 dB.
• The problem: the band $7.5<fw<15$ has no row at all, so the table jumps from $3.8<fw<7.5$ straight to $fw>15$. A duct-borne calculation lands in that band routinely: a $24\text{in}$ elbow at 500 Hz has $fw=12$.
• Evidence: the same data adapted from the same ASHRAE source appear in Bies, Hansen & Howard, Engineering Noise Control 5e, Table 8.11, indexed by $W/\lambda$ ($=0.074fw$). Its round-elbow column has six rows, 0/1/2/3/3/3, and gives 3 dB for $0.55\le W/\lambda <1.11$, which is exactly the $7.5<fw<15$ band Long omits. Long’s four rows map onto Bies’ six as follows: the first three agree entry for entry, the fourth ($fw>15$, 3 dB) legitimately merges Bies’ two identical top rows, and the band with no row is Bies’ fourth. An earlier revision of this entry said that “Tables 14.5 and 14.6 both carry six rows” and that “the other five rows of the two tables agree entry for entry”; on the page, Table 14.5 carries six rows and Table 14.6 five (it merges the same two identical top bands, legitimately), and Table 14.7 prints four, so neither count is right. Verified on PDF page 542 (printed p. 541) and PDF page 541 (printed p. 540) of Long, Architectural Acoustics 2e (2014).
• Library behaviour: elbow_insertion_loss in hvac.py carries the six-row round column with 3 dB in the missing band, pinned by test_elbow_tables_by_frequency_width_product (tests/noise_control/test_hvac_long.py).
• Status: unreported (textbook rather than a standard).

• Location: Chapter 13, Eq. 13.28 (printed p. 521), the normalised pressure-drop coefficient $\xi =334.9\cdot \Delta P/({\rho }_0{U}_G^2)$ of the diffuser sound-power model.
• The print: the nomenclature under the equation gives “U_G = flow velocity prior to the diffuser (ft/min)” and, on the next line, ”= Q/(60·S_G) (for Q in cfm)”.
• The problem: the two statements contradict each other. $Q$ in ft³/min divided by $60S_G$ is a velocity in ft/s, not ft/min, and only the ft/s reading makes the constant right: $334.9/{\rho }_0$ with ${\rho }_0=0.075{\text{lb/ft}}^3$ is $4465\cdot \Delta P/U^2$, which is the standard velocity-pressure relation $\Delta P/(U/4005{)}^2$ only when $U$ is converted from ft/s. Read as ft/min the coefficient comes out 3600 times too small. Eq. 13.27 itself declares $U_G$ in ft/s, so the “(ft/min)” label under Eq. 13.28 is the odd one out.
• Evidence: dimensional check of $Q/(60S_G)$; reconstruction of the $334.9/{\rho }_0$ constant from the velocity-pressure relation; and the peak frequency. What does not discriminate is the overall level: Eq. 13.27 carries $30{\log }_{10}\xi +60{\log }_{10}{U}_G$, and substituting Eq. 13.28 makes the velocity cancel identically, $30{\log }_{10}\xi +60{\log }_{10}{U}_G=30{\log }_{10}(334.9\Delta P/{\rho }_0)$. For the Table 14.9 supply diffuser ($S_G=4{\text{ft}}^2$, $Q=312$ cfm, $\Delta P=0.05$ in w.g.) both readings therefore return the same $L_W=45.18\text{dB}$. An earlier revision of this entry claimed that the ft/min reading “misses it by 100 dB”, which is arithmetically impossible for a quantity that does not depend on the velocity at all. What does discriminate is Eq. 13.32, $f_P=48.8U_G$, which is the only other place $U_G$ enters: read in ft/s the approach velocity is $1.3\text{ft/s}$ and the peak falls at 63.4 Hz, i.e. in the 63 Hz octave, so the Eq. 13.31 shape puts 33.4 dB in that band against the printed 33; read in ft/min it is $78\text{ft/min}$, the peak moves to 3 806 Hz, and the same shape puts -8.2 dB in the 63 Hz band. Verified on PDF page 522 (printed p. 521) of Long, Architectural Acoustics 2e (2014).
• Library behaviour: diffuser_sound_power in hvac.py reads $U_G$ in ft/s internally (SI at the interface), with the Table 14.9 row pinned by test_diffuser_sound_power_reproduces_the_table_14_9_row (tests/noise_control/test_hvac_long.py) and the conformance check “Long 2e Eqs. 13.27-13.33”.
• Status: unreported (textbook rather than a standard).

• Non-normative source (textbook).
• Location: section 8.4.2, the caption of Figure 8.37 on printed p. 320 / pdf p. 341, which labels the predicted improvement curves of two floor coverings laid on a heavyweight floor.
• The print: “Predicted improvement with a linear model: stiffness of carpet squares 3.2·10^6 N/m, vinyl covering 5.2·10^6 N/m.” (Vigran writes the decimal separator as a period.)
• The problem: the carpet exponent is one order too high. The body text introducing the figure, on printed p. 321, says of the carpet squares that “we have assumed that the covering has the same stiffness as used in Figure 8.36”, and Figure 8.36 is labelled $s=3.2\cdot 10^5\text{N/m}$ inside the plot, the same value the body text on printed p. 320 gives for it. The vinyl value in the same caption is correct.
• Evidence: printed p. 320 states $3.2\cdot 10^5\text{N/m}$ “giving a resonance frequency f0 of approximately 130 Hz with a hammer mass of 0.5 kg”, and $\sqrt{3.2\cdot 10^5/0.5}/(2\pi )=127.3\text{Hz}$ reproduces that while $\sqrt{3.2\cdot 10^6/0.5}/(2\pi )=402.6\text{Hz}$ is a frequency that appears nowhere in the section. The same arithmetic applied to the caption’s vinyl value gives $\sqrt{5.2\cdot 10^6/0.5}/(2\pi )=513.3\text{Hz}$ against the “approximately 510 Hz” printed on p. 321, which fixes the formula and the hammer mass the author used. Graphically, the two dashed prediction curves of Fig. 8.37 are about two octaves apart, matching the stiffness ratio $5.2\cdot 10^6/(3.2\cdot 10^5)=16.25$ (a factor 4.03 in frequency) and not $5.2\cdot 10^6/(3.2\cdot 10^6)=1.63$ (a factor 1.27). Verified on PDF page 341 (printed p. 320) of Vigran, Building Acoustics:2008, on which both caption exponents read 6 unambiguously and the body text of the same page reads $3.2\cdot 10^5\text{N/m}$, with the surrounding argument read on PDF page 340 (printed p. 319) and PDF page 342 (printed p. 321) of the same edition.
• Library behaviour: none needed; the library takes the covering stiffness from the user through covering_contact_stiffness, and the printed cut-off frequencies it is anchored on come from Hopkins rather than from this caption.
• Status: unreported.

• Location: Section 6.6.1, Eq. (6.56), the coupling loss factor of two homogeneous plates joined by $N$ point connections (printed p. 418).
• The print: the denominator bracket $({\rho }_{s1}^2{h}_1^2{c}_{L1}^2+{\rho }_{s2}^2{h}_2^2{c}_{L2}^2)$ appears to the first power.
• The problem: as printed the expression is not dimensionless. The prefactor $4N{h}_1{c}_{L1}/(\sqrt{3}\omega S_1)$ already has the dimensions of ${\text{m}}^2{\text{s}}^{-1}$ over ${\text{m}}^2{\text{s}}^{-1}$, i.e. unity, so the remaining ratio of the two bracketed products must be dimensionless too. That requires the sum to be squared, $A_1{A}_2/(A_1+A_2{)}^2$.
• Evidence: the book’s own answer to problem 6.13 (printed p. 617). With the squared denominator the twelve-bolt aluminium pair gives ${\eta }_{12}=1.43\cdot 10^{-2}$ at 125 Hz against the printed $1.44\cdot 10^{-2}$, and matches the whole 125 Hz to 2 kHz column to better than $0.7\%$; with the printed (unsquared) denominator the result is not a loss factor at all. Verified on PDF page 438 (printed p. 418) of Norton & Karczub, Fundamentals of Noise and Vibration Analysis for Engineers 2e:2003.
• Library behaviour: point_connection_coupling_loss_factor in junction_transmission.py implements the squared form, with the printed column pinned by a regression test (tests/vibration/structural/test_junction_transmission.py) and a note at the formula.
• Status: unreported (textbook rather than a standard).

• Location: Answers to problems, problem 6.13 (printed p. 617), the two ${\eta }_{21}$ columns of the welded and bolted tables.
• The print: for the two aluminium plates (plate 1: 3 mm, 2.5 m × 1.2 m; plate 2: 5.5 mm, 2.0 m × 1.2 m) the answer gives, at 125 Hz, ${\eta }_{21}=5.77\cdot 10^{-3}$ (welded) and $2.64\cdot 10^{-2}$ (bolted).
• The problem: both columns are exactly the corresponding ${\eta }_{12}$ column multiplied by $h_2/h_1=1.833$. The SEA consistency relationship is $n_1{\eta }_{12}=n_2{\eta }_{21}$ (Eq. 6.8) with the flat-plate modal density $n=S\sqrt{12}/(2c_{L}h)$ of Eq. (6.25), so the correct factor is $n_1/n_2=(S_1{h}_2)/(S_2{h}_1)=2.292$. The printed column drops the plate area ratio $S_1/S_2=1.25$.
• Evidence: the ratio of the printed columns is 1.8333 to five digits in every band of both tables, which is $h_2/h_1$ exactly; the ${\eta }_{12}$ columns themselves reproduce from Eqs. (6.52) to (6.56) to better than 0.7 %. Verified on PDF page 637 (printed p. 617) of Norton & Karczub 2e:2003, the page that carries both answer tables.
• Library behaviour: the ${\eta }_{12}$ columns are used as the regression oracle; ${\eta }_{21}$ is obtained from Eq. (6.8) with the full modal densities, and a test pins the 2.292 ratio explicitly (tests/vibration/structural/test_junction_transmission.py).
• Status: unreported (textbook rather than a standard).

• Location: Problems, problem 6.10 (printed pp. 593-594) and its answer (printed p. 617): a satellite platform coupled to an aluminium cylinder, 500 Hz octave, printed answers ${\eta }_{12}=4.26\cdot 10^{-4}$, ${\eta }_{21}=3.92\cdot 10^{-4}$ and ${\Pi }_{\text{in}}=1.31\text{W}$.
• The print: the statement gives the aluminium platform as “5 mm thick and 3.5 m × 3 m”, i.e. 10.5 m².
• The problem: that area is inconsistent with the three printed answers. Eq. (6.12) fixes $E_1/E_2=({\eta }_2+{\eta }_{21})/{\eta }_{12}=6.554$ from the printed loss factors alone, whereas the stated geometry with the printed velocities (27.2 and 13.2 mm/s) gives 7.88. The energy ratio is independent of the modal densities and of the wave speed, so no choice of those can reconcile it; only the platform area can. The area the answers imply is 8.73 m², which is $3.5\times 3$ minus the $\pi (0.75\text{m}{)}^2$ footprint of the cylinder that Fig. P6.10 shows passing through the platform.
• Evidence: with 8.73 m² the inversion of Eqs. (6.15), (6.8) and (6.10) returns ${\eta }_{12}=4.256\cdot 10^{-4}$, ${\eta }_{21}=3.910\cdot 10^{-4}$ and ${\Pi }_{\text{in}}=1.306\text{W}$, i.e. all three printed answers within 0.4 %; the cylinder’s own energy and modal density come out unchanged either way. Verified on PDF page 613 (printed p. 593), which carries the statement and its dimensions, and PDF page 637 (printed p. 617), which carries the three answers, of Norton & Karczub 2e:2003.
• Library behaviour: power_injection_clf in experimental_sea.py implements the inversion as published; the regression test uses the free platform area and documents the discrepancy (tests/vibration/structural/test_experimental_sea.py).
• Status: unreported (textbook rather than a standard).

• Location: Problems, problem 3.14 (printed p. 580) and its answer (printed p. 611): the octave-band transmission loss of a 20 mm particle board panel.
• The print: the statement gives the panel a structural loss factor of “~1.5 × 10⁻²”; the answer gives 27 dB at 8 kHz and 38.6 dB at 16 kHz.
• The problem: those two values are above the panel’s critical frequency (4885 Hz for Appendix 4 particle board, $f_{c}t=97.7\text{m/s}$) and therefore follow Cremer’s Eq. (3.110), which contains $10{\log }_{10}(\eta )$. With $\eta =1.5\cdot 10^{-2}$ the equation gives 37.0 dB and 48.5 dB, ten decibels above the printed answers; with $\eta =1.5\cdot 10^{-3}$ it gives 27.0 dB and 38.5 dB.
• Evidence: the 10 dB offset is exactly one decade of $10{\log }_{10}(\eta )$, and the frequency dependence of the printed pair independently fixes $f_c=4939\text{Hz}$ against the Appendix 4 value of 4885 Hz. The eight values below coincidence reproduce exactly from Eq. (3.104) and do not involve $\eta$. The discrepancy is a decade in a printed exponent, so the two figures were read as images rather than through the text layer. Verified on PDF page 600 (printed p. 580) and PDF page 631 (printed p. 611) of Norton & Karczub 2e (2003).
• Library behaviour: the regression test uses $\eta =1.5\cdot 10^{-3}$, the value the printed answers require (tests/building/prediction/test_panel_transmission.py).
• Status: unreported (textbook rather than a standard).

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• Location: Section 9.2.3.2, Eq. (9.18) (printed p. 339), the transmission factor of the one-dimensional suspended-ceiling plenum model after Mechel (1980).
• The print: the denominator reads $m_S{L}_S\cdot m_R{L}_{R}h$ with the unprimed $m_R$, while the exponent of the same expression carries the primed $m_R^{\prime }=m_R+s_R{\tau }_R/h$ of Eq. (9.17).
• The problem: the two sides of the plenum are integrated the same way. The receiving-side integral is ${\int }_0^{L_R}\exp (-\epsilon m_R^{\prime }x)dx=(1-\exp (-\epsilon m_R^{\prime }{L}_R))/(\epsilon m_R^{\prime })$, so the factor that normalises it must be $m_R^{\prime }{L}_R$, exactly as the source-side one is $m_S{L}_S$. Read literally, the printed expression is not a transmission factor at all: it carries a spurious $m_R^{\prime }/m_R=1+s_R{\tau }_R/(h{m}_R)$, so it grows without bound as the plenum damping falls. Two consequences are visible with ordinary inputs ($L_S=L_R=5\text{m}$, $h=0.6\text{m}$, $R_S=R_R=25\text{dB}$, $\epsilon =2$, $s_S=s_R=0.5$): the model diverges as the plenum damping vanishes, giving $R_{\text{cl}}=40.26\text{dB}$ at $m_R=0.01\text{1/m}$ but only 26.48 dB at $10^{-4}$ and 6.64 dB at $10^{-6}$, against the finite 40.85 dB that the derived reading returns for the same bare plenum, where the leakage term $s_R{\tau }_R/h$ bounds the path; a plenum with no absorber at all is therefore predicted arbitrarily worse than the leak-limited value rather than equal to it. It also breaks energy conservation, returning ${\tau }_{\text{cl}}=4.45$ at $R_S=R_R=6\text{dB}$, $m_R=0.01$ and ${\tau }_{\text{cl}}=829$ at $R_S=R_R=0\text{dB}$, $m_R=10^{-3}$.
• Evidence: with $m_R^{\prime }$ in the denominator every one of those pathologies disappears: ${\tau }_{\text{cl}}$ flattens onto the leak-limited value as the damping vanishes, where the printed form keeps growing, and is bounded above by 1 because $(1-\exp (-\epsilon m_R^{\prime }{L}_R))/(\epsilon m_R^{\prime }{L}_R)\le 1$, and reduces to Vigran’s own small-attenuation result, Eq. (9.19) ${\tau }_{\text{cl}}={\epsilon }^2{\tau }_S{\tau }_R{L}_R/(4h)$, whenever $m_S{L}_S$ and $m_R^{\prime }{L}_R$ are both small. With the printed $m_R$ the same limit picks up the factor $m_R^{\prime }/m_R$, which diverges, so Eq. (9.18) as printed does not reduce to Eq. (9.19) at all: the two equations the book presents as a pair are inconsistent with each other. Verified on PDF page 361 (printed p. 339) of Vigran, Building Acoustics:2008, which shows the denominator carrying the unprimed $m_R$ while the exponent of the same expression carries the primed $m_R^{\prime }$ of Eq. (9.17).
• Library behaviour: plenum_flanking_reduction_index in ceiling_plenum.py implements the derived $m_R^{\prime }$ in both the exponent and the denominator, with the reading documented at the formula, and rejects a transmission factor above unity rather than reporting a negative sound reduction index. Tests pin the physics the model owes (monotonicity in the damping, the ${\tau }_{\text{cl}}\le 1$ bound, the size of the Eq. (9.17) leakage term at a realistic ceiling) and the one property that separates the two readings: a bare plenum no worse than the undamped Eq. (9.20) value (tests/building/prediction/test_ceiling_plenum.py).
• Status: unreported (textbook rather than a standard). Mechel’s original 1980 paper, which Vigran reproduces, was not available to check whether the misprint originates there.

• Location: Annex IV, section A.3.3, the $K_f$ (low-frequency) and $K_i$ (impulsive) correction tables, middle row of each.
• The print: both tables print the 3 dB row as “Si 10 > Lf <= 15” and “Si 10 > Li <= 15” respectively (BOE-A-2007-18397, consolidated text).
• The problem: the condition as printed is unsatisfiable. It reads “10 greater than Lf” and “Lf at most 15” simultaneously, which would select levels below 10 dB, but the row above it already assigns those to 0 dB (“Si Lf <= 10”) and the row below covers “Si Lf > 15”. The three rows only partition the range under the reading $10<L_f\le 15$, so the ”>” is a typeset inversion of ”<”.
• Evidence: the bracketing rows leave no other consistent reading; the identical construction appears in both tables, and the equivalent tables in the autonomous-community noise regulations that transpose this Annex print 10 < Lf <= 15. Verified on PDF page 26 (printed p. 26) of Real Decreto 1367/2007, BOE-A-2007-18397 consolidated text, on which the ”>” of both middle rows is unambiguous against the ”<=” glyphs of the same cell.
• Library behaviour: low_frequency_correction and impulsive_correction implement $10<L\le 15$, with a regression test pinning the three branches at the 10 dB and 15 dB boundaries.
• Status: unreported (national regulation, not a standards body).

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• Location: the Annex, point 2.2.1, second paragraph under the heading “Traffic flow” (OJ L 168, 1.7.2015, p. 8).
• The print: “these sound power levels are calculated for each octave band i from 125 Hz to 4 kHz”.
• The problem: the road source model contradicts its own coefficient database. Every band-dependent table of Appendix F, both in the 2015 text and in the version replaced by (EU) 2021/1226, is printed over the eight octave bands 63 Hz to 8 kHz (Table F-3 has no frequency columns at all), and point 2.1.1 of the same Annex defines the frequency range of the method as 63 Hz to 8 kHz. A calculation restricted to 125 Hz - 4 kHz would silently discard the 63 Hz and 8 kHz bands, which Appendix F tabulates like every other.
• Evidence: corrected by the corrigendum published in OJ L 5, 10.1.2018, p. 35, which reads in full: ‘On page 8, in the Annex, in point 2.2.1, in the second paragraph under the heading “Traffic flow”: for: “each octave band i from 125 Hz to 4 kHz”, read: “each octave band i from 63 Hz to 8 kHz”’. The same corrigendum also adds “octave bands” to the frequency range of 2.1.1. Verified on PDF page 8 (printed p. L 168/8) of Commission Directive (EU) 2015/996:2015 for the printed restriction, on PDF page 1 (printed p. L 5/35) of the corrigendum for both items, and on PDF page 4 (printed p. L 168/4) and PDF page 124 (printed p. L 168/124) of the Directive for the conformant range.
• Library behaviour: cnossos_road works over the corrected 63 Hz to 8 kHz grid (ROAD_OCTAVE_BANDS), pinned by test_octave_bands_are_the_corrected_range and by the workbook cases, whose published levels cover all eight bands.
• Status: corrected by the issuing body (corrigendum of 10 January 2018); recorded because the uncorrected 2015 text is still the one most often downloaded and quoted.

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Textbook, not a standard.

• Location: Section 9.1.1.2.4 (printed p. 457), the transition range between the mode-stripping and single-mode regimes of the Weston flux model.

• The print: $r_{\text{MS}}\approx k^2{H}_e^3/(9\eta )$, where $H$ is the water depth, $H_e$ the Weston effective depth of Eq. (9.55), $k=\omega /c_w$ and $\eta$ the reflection loss gradient.

• The problem: the sentence immediately above it prescribes the derivation, “estimated by equating θ_n and θ_eff with n = 3/2”. The two angles are four printed pages apart, not on the same page as an earlier revision of this entry stated:

  • Eq. (9.47), ${\theta }_{\text{eff}}=(\pi H/(4\eta r){)}^{1/2}$, printed p. 453, with the true water depth $H$ (it comes from the multipath integral Eq. (9.46), whose $1/(rH)$ prefactor is the cylinder area $A_{\text{CS}}=2\pi rH$ of Eq. (9.44), so $H$ is the depth that counts bottom bounces);
  • Eq. (9.56), ${\theta }_n\approx n\pi /(k{H}_e)$, printed p. 457, with the effective depth $H_e$ (mode angles are set by the apparent pressure-release boundary).

  Equating them at $n=3/2$ gives $\pi H/(4\eta r)=9{\pi }^2/(4k^2{H}_e^2)$, that is $r_{\text{MS}}=k^2{H}_e^{2}H/(9\pi \eta )$. The printed form is larger by $\pi H_e/H$. The factor $\pi$ is unconditional: it survives even if $H_e$ is substituted for $H$ in Eq. (9.47), which is presumably how the printed $H_e^3$ arose, and that reading would give $k^2{H}_e^3/(9\pi \eta )$, still $\pi$ below the print. The residual $H_e/H$ is the depth substitution itself, and it tends to 1 at high frequency. The other transition of the same section, Eq. (9.50) $r_{\text{CS}}=\pi H/(4\eta {\psi }_c^2)$, follows its own derivation exactly (it is where Eq. (9.42) and Eq. (9.49) cross), so the defect is confined to Eq. (9.57).

• Evidence: the symbolic re-derivation above, checked numerically for $H=50\text{m}$, $f=250\text{Hz}$, $c_w=1500\text{m/s}$ over the Table 9.1 sand seabed ($\eta =0.28\text{Np/rad}$, ${\psi }_c=33.56^{\circ }$, $H_e=53.63\text{m}$, $k=1.047{\text{m}}^{-1}$):

  	$r_{\text{MS}}$	${\theta }_{\text{eff}}$ there (Eq. 9.47)
  derivation, $k^2{H}_e^{2}H/(9\pi \eta )$	19.9 km	4.808°
  printed Eq. (9.57), $k^2{H}_e^3/(9\eta )$	67.1 km	2.619°

  The ratio $67.1/19.9$ is $\pi H_e/H=3.3695$ to every digit carried. The angle column is an independent check that does not depend on how the derivation is read: the first two mode angles of Eq. (9.56) are ${\theta }_1=3.205^{\circ }$ and ${\theta }_2=6.410^{\circ }$, so ${\theta }_{3/2}=4.808^{\circ }$. At the derived range the effective angle is exactly ${\theta }_{3/2}$, halfway between the first two modes, which is what the text asks for. At the printed range it has fallen to 2.619°, below ${\theta }_1$ itself: the second mode would have been stripped long before, so that range cannot be where the single-mode regime begins. Both printed formulae are confirmed on PDF page 483 (printed p. 453) and PDF page 487 (printed p. 457) of Ainslie, Principles of Sonar Performance Modelling (2010).

• Library behaviour: weston_regime_boundaries in propagation/weston_regimes.py implements the derivation-consistent $k^2{H}_e^{2}H/(9\pi \eta )$, which is also what keeps ${\theta }_{\text{eff}}$ defined with $H$ everywhere the module evaluates Eq. (9.47). The equating rule is pinned by test_mode_stripping_boundary_equates_theta_eff_with_mode_3_over_2, which rebuilds both angles from the printed equations rather than from the implementation, and the shared definition of ${\theta }_{\text{eff}}$ by test_composite_loss_and_the_boundary_use_the_same_effective_angle (both in tests/underwater/propagation/test_weston_regimes.py).

• Status: unreported (textbook rather than a standard).

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Regulatory guidance document, not a standard.

• Location: Table 5 (printed p. 25), repeated as Table ES2 (printed p. 3) and again as Table 8 (printed p. 35): the auditory weighting parameter $C$ of the otariid pinniped in-water group (OW / OCW).
• The print: $C=1.37\text{dB}$.
• The problem: the correct value is 1.36 dB. NMFS states so itself in the table’s own footnote: “During the public comment period, an error was identified with the Navy’s rounding, where this value should be 1.36, instead of 1.37. Because this is such a minor error and to remain consistent with the Navy, NMFS decided rely upon the value the Navy originally provided.” The document therefore knowingly publishes the wrong digit.
• Evidence: independent recomputation of $C$ from its own definition, the negated peak of $W(f)$, with the same row’s parameters $a=1.58$, $b=5$, $f_1=2.53\text{kHz}$, $f_2=43.8\text{kHz}$: $C=1.3643\text{dB}$, which rounds to 1.36. The published weighted TTS onset of the same row ($179\text{dB}=K+C$ with $K=178$) is unaffected by the third digit. The same recomputation reproduces every other row of the table to the printed two decimals, so the OW row is the only one that does not round from its own parameters. Verified on PDF page 36 (printed p. 25), PDF page 14 (printed p. 3) and PDF page 46 (printed p. 35) of NMFS Updated Technical Guidance v3.0:2024, all three carrying 1.37 with the identical footnote.
• Library behaviour: bioacoustics/weighting.py implements 1.36 and keeps the printed 1.37 available as WeightingParameters.c_db_as_printed, so an assessment that must reproduce the published table verbatim still can. Pinned by test_nmfs_2024_otariid_c_uses_the_corrected_1_36.
• Status: unreported (the issuing body has already documented it).

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Peer-reviewed journal paper, not a standard.

• Location: Table 7 (printed p. 156), the impulsive-noise TTS and PTS onset criteria; the two in-air carnivore rows PCA and OCA.
• The print: PCA TTS peak SPL 138 and PTS peak SPL 144; OCA TTS peak SPL 161 and PTS peak SPL 167 $\text{dB re }20\mu \text{Pa}$.
• The problem: all four are typographical errors. The authors’ own errata (Aquatic Mammals 45(5), 569-572, DOI 10.1578/AM.45.5.2019.569) names all four on printed p. 569, “There are four typographical errors in Table 7 on page 156”, and reprints the corrected table on printed p. 570: PCA 155 and 161, OCA 170 and 176. The same errata also corrects the column headed “B” in Table 5 to the parameter b of Eq. (2), which it likewise calls a typographical error.
• Evidence: the errata itself, which names each wrong value and its replacement, corroborated by the article’s own extrapolation rule. Note first what does not discriminate. The PTS peak = TTS peak + 6 dB rule of printed p. 155 is satisfied by the printed pair as well ($144-138=6$, just as $161-155=6$), so it says nothing about which pair is right. Nor does the duplication visible in the printed rows, where the peak-SPL TTS entry equals that same row’s PTS-onset SEL entry (PCA 123 / 138 / 138 / 144 and OCA 146 / 161 / 161 / 167, reading TTS SEL, TTS peak, PTS SEL, PTS peak): for these two in-air rows that equality is forced by two rules the article states on printed p. 155, both adding 15 dB to the same base TTS SEL, so it would hold whatever the SEL values were. An earlier revision of this entry read that equality as the signature of a column slip; it is instead the printed table being internally consistent with the article’s own in-air method, which is what makes the errata the only thing that settles the matter.
  • Value. The corrected numbers are close to what the article’s extrapolation rule produces, with the caveat that the rule is not stated for these rows. Printed p. 155 sets the impulsive peak-SPL TTS onset of a group without direct data at the hearing threshold at the frequency of best sensitivity $f_0$ plus 159 dB, and restricts that rule explicitly to the in-water groups: “For other species groups in water (LF, SI, PCW, and OCW), 159 dB was added to the value of the hearing threshold at f₀”. It works the rule through for PCW: “Peak SPL TTS onset was estimated as 212 dB re 1 µPa (53 dB at f₀ + 159 dB)”. Evaluating the Table 2 group audiogram at the Table 4 $f_0$ reproduces the three in-water rows the errata does not touch (SI 219.6 against a published 220; PCW 212.5 against 212; OCW 226.1 against 226), which validates the rule where the article applies it. Extending it to the two in-air carnivore rows, which the article does not do, gives PCA $-4.6\text{dB re }20\mu \text{Pa}$ at 2.3 kHz and OCA $11.4\text{dB re }20\mu \text{Pa}$ at 10 kHz, hence 154.4 and 170.4. Those reproduce the corrected 155 and 170 to within 0.6 dB and are 16 dB and 9 dB away from the printed 138 and 161, which is what makes them corroborating rather than confirming; note that 154.4 rounds to 154, not to 155, and an earlier revision of this entry claimed that it rounded to the corrected value.
  • A second, unrepaired inconsistency. Printed p. 155 states that for the in-air carnivores specifically “a nominal 15 dB offset is used … between the SEL-based TTS threshold and the peak SPL-based threshold”, which reproduces the printed 138 and 161 from the SEL column. That sentence, not the +159 dB rule, is the one the article’s own method applies to PCA and OCA. The errata resolves the conflict in favour of values consistent with the +159 dB rule, so it supersedes the sentence as well as the table; the sentence is left standing in the article. Verified on PDF page 31 (printed p. 155) and PDF page 32 (printed p. 156) of Southall et al. (2019), Aquatic Mammals 45(2), which carry the “in water (LF, SI, PCW, and OCW)” restriction, the 15 dB in-air offset in the same paragraph, both statements of the +6 dB rule, and the article’s Table 7 with the PCA row 123 / 138 / 138 / 144 and the OCA row 146 / 161 / 161 / 167. The errata is a publication of its own, Aquatic Mammals 45(5), 569-572, bound at the end of the copy the authors distribute: verified there on PDF page 109 (printed p. 569), which names all four values and their replacements, and PDF page 110 (printed p. 570), which reprints Table 7 with PCA 123 / 155 / 138 / 161 and OCA 146 / 170 / 161 / 176.
• Library behaviour: the errata-corrected values are the ones implemented in bioacoustics/weighting.py, pinned by test_southall_table_7_errata_values_are_implemented, with the +159 dB rule itself checked against the audiogram in test_southall_impulsive_peak_spl_is_threshold_at_f0_plus_159_db for the in-water groups the article restricts it to and, separately and with the extrapolation labelled as such, for PCA and OCA.
• Status: reported by the authors themselves (errata published 2019).

• Location: the “Definition” paragraph of Wheel and rail roughness (OJ L 168, 1.7.2015, p. 19) and the first paragraph after formula (2.3.11) (p. 21).
• The print: “it shall be converted to a frequency spectrum f = v/λ, where f is the centre band frequency of a given 1/3 octave band in Hz, λ is the wavelength in m, and v is the train speed in km/h”, and, for impact noise, “using the relation λ = v/f, where f is the 1/3 octave band centre frequency in Hz and v is the s-th vehicle speed of the t-th vehicle type in km/h”.
• The problem: dimensionally impossible. A frequency in hertz is a speed in metres per second divided by a wavelength in metres; reading the speed in km/h into $f=v/\lambda$ multiplies every frequency by 3,6, placing the whole roughness spectrum a factor 3,6 too high in frequency, which is more than an octave and a half.
• Evidence: verified on PDF page 19 (printed p. L 168/19) and PDF page 21 (printed p. L 168/21) of Directive (EU) 2015/996. The corrigendum of OJ L 5, 10.1.2018, p. 35 replaces “km/h” by “m/s” in both places. The flow equation (2.3.2) genuinely does take its speed in km/h, which is what makes the misprint plausible.
• Library behaviour: roughness_to_frequency converts the speed to m/s before dividing, as corrected, and its docstring says so. The reference implementation the Commission published with the source module does the same, and the 123 committed workbook cases would not reproduce otherwise.
• Status: unreported (corrected by the issuing body in 2018).

• Location: Table G-1, “Coefficients Lr,TR,i and Lr,VEH,i for rail and wheel roughness”, second table (OJ L 168, 1.7.2015, pp. 130-131).
• The print: the second table is headed $L_{r,VEH,i}$, the same symbol as the first.
• The problem: its two columns are “EN ISO 3095:2013 (Well maintained and very smooth)” and “Average network (Normally maintained smooth)”, which are the rail-roughness classes E and M of digit 2 of the track descriptor in Table [2.3.b]. The table is the rail roughness $L_{r,TR,i}$, the quantity the table’s own title announces and which is otherwise missing from Appendix G.
• Evidence: verified on PDF page 130 (printed p. L 168/130) of Directive (EU) 2015/996:2015, the page carrying the header of the second table. The corrigendum of OJ L 5, 10.1.2018 re-titles it $L_{r,TR,i}$, and Commission Delegated Directive (EU) 2021/1226 Annex point (20)(a) reprints it under that symbol when it replaces it, verified on PDF page 35 (printed p. L 269/99) of that Directive.
• Library behaviour: rail_roughness returns the second table of G-1 as the rail roughness of (2.3.7) and wheel_roughness returns the first as the wheel roughness, which is the only assignment under which the classes of Table [2.3.b] can be reached at all.
• Status: unreported (corrected by the issuing body in 2018).

• Location: Table G-5, “Coefficients LW,0,idling for traction noise”, the 6 350 Hz row of the “Diesel locomotive (c. 2 200 kW)” pair (OJ L 168, 1.7.2015, p. 138).
• The print: Source A 31,4 dB and Source B 30,7 dB.
• The problem: both are about 50 dB below their own neighbours in the same column: 90,5 / 89,5 dB at 5 000 Hz and 81,2 / 80,6 dB at 8 000 Hz. No physical traction source has a 50 dB notch one third of an octave wide, and no other column of the table has anything comparable. The leading digit 8 was lost.
• Evidence: verified on PDF page 138 (printed p. L 168/138) of Directive (EU) 2015/996:2015, which carries the 5 000, 6 350 and 8 000 Hz rows and the “Diesel locomotive (c. 2 200 kW)” column header. Commission Delegated Directive (EU) 2021/1226 Annex point (20)(f), verified on PDF page 39 (printed p. L 269/103) of that Directive, replaces the 4th column, 25th row by “81,4” and the 5th column, 25th row by “80,7”, restoring the monotone roll-off. The same two values appear as 31,41 and 30,71 in the IMAGINE catalogue file the Commission distributes with its reference source module, so the error predates the Directive.
• Library behaviour: ships the corrected 81,4 / 80,7 and pins them, together with the assertion that neither value is more than 10 dB from either neighbour, in test_table_g5_carries_the_2021_correction_at_6300_hz.
• Status: unreported (corrected by the issuing body in 2021).

• Location: the frequency column of Tables G-3, G-5 and G-6 and the wavelength column of Table G-1 (OJ L 168, 1.7.2015, pp. 129-140).
• The print: the 1/3-octave band centres are labelled 316 Hz, 3 160 Hz and 6 350 Hz, and the wavelengths 120 mm, 12 mm, 3,2 mm and 1,2 mm.
• The problem: neither series is the preferred one. The nominal 1/3-octave centres of IEC 61260-1 are 315, 3 150 and 6 300 Hz, and the R10 preferred numbers around those wavelengths are 125, 12,5, 3,15 and 1,25 mm. The Commission’s own catalogue files, distributed with the reference source module, use the preferred wavelength series throughout.
• Evidence: verified on PDF pages 129, 130, 131, 133, 134, 135, 137 and 138 (printed pp. L 168/129 to L 168/138) of Directive (EU) 2015/996:2015, which carry every occurrence of the four wavelengths and of the three band labels. Commission Delegated Directive (EU) 2021/1226 Annex point (20)(c) replaces the $L_{H,TR,i}$ section of Table G-3 outright and points (20)(d), (f) and (g) replace the three frequency labels in the remaining sections and in Tables G-5 and G-6; the tables it replaces outright carry the preferred wavelengths. But point (20)(a) replaces only “the second table” of Table G-1, so the wavelength labels 120, 12, 3,2 and 1,2 mm still stand on the first table of G-1, the wheel roughness $L_{r,VEH,i}$, which is the one table that keeps them.
• Library behaviour: the frequency grid is the IEC 61260-1 one throughout. The wavelength grids are kept as printed, one per table, and each roughness spectrum is resampled on its own grid rather than forced onto a common one, which is what _WAVELENGTHS_WHEEL and _WAVELENGTHS_STANDARD are for; the difference between the two is pinned by test_wheel_roughness_keeps_the_non_standard_wavelength_grid.
• Status: unreported (frequency labels corrected by the issuing body in 2021; the wheel-roughness wavelength labels stand).

• Location: the Squeal paragraph (OJ L 168, 1.7.2015, p. 21).
• The print: “The emission level to be used is determined for curves with radius below or equal to 500 m and for sharper curves and branch-outs of points with radii below 300 m”, and then “squeal noise shall be considered by adding 8 dB for R < 300 m and 5 dB for 300 m < R < 500 m”.
• The problem: the two open intervals leave $R=300\text{m}$ and $R=500\text{m}$ with no excess at all, and $R=500\text{m}$ is explicitly inside the scope the same paragraph has just set. A 500 m curve therefore falls out of a rule written to include it.
• Evidence: verified on PDF page 21 (printed p. L 168/21) of Directive (EU) 2015/996:2015, on which both inequalities of the rule sentence are strict while the scope sentence above them reads “below or equal to 500 m”. Commission Delegated Directive (EU) 2021/1226 Annex point (4)(b), verified on PDF page 4 (printed p. L 269/68) of that Directive, replaces the paragraph with a table whose intervals are closed, “R <= 300 m” and “300 m < R <= 500 m”.
• Library behaviour: curve_squeal_excess implements the 2021 table, so $R=300\text{m}$ returns 8 dB and $R=500\text{m}$ returns 5 dB; the boundaries are pinned in test_curve_squeal_rule_of_2021.
• Status: unreported (corrected by the issuing body in 2021).

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Textbook, not a standard.

• Location: Sect. 6.5.2 (printed p. 123), the second form of the shear-wave velocity ratio ${\mu }_3$.
• The print: ${\mu }_3=(N{\delta }_3^2-{\omega }^2{\rho }_{11})/({\omega }^2{\rho }_{22})$, offered as an alternative to Eq. (6.84), ${\mu }_3=-{\rho }_{12}/{\rho }_{22}$.
• The problem: the two printed forms are not equal. Substituting the shear wavenumber of Eq. (6.83), ${\delta }_3^2=({\omega }^2/N)({\rho }_{11}{\rho }_{22}-{\rho }_{12}^2)/{\rho }_{22}$, into the printed Eq. (6.85) gives $-{\rho }_{12}^2/{\rho }_{22}^2$, which is Eq. (6.84) multiplied by the spurious factor ${\rho }_{12}/{\rho }_{22}$. The denominator should read ${\omega }^2{\rho }_{12}$.
• Evidence: the book’s own derivation. Eq. (6.80), printed p. 122, is $-{\omega }^2{\rho }_{11}{\psi }_s-{\omega }^2{\rho }_{12}{\psi }_f=N{\nabla }^2{\psi }_s=-N{\delta }_3^2{\psi }_s$, so $(N{\delta }_3^2-{\omega }^2{\rho }_{11}){\psi }_s={\omega }^2{\rho }_{12}{\psi }_f$ and therefore ${\mu }_3={\psi }_f/{\psi }_s=(N{\delta }_3^2-{\omega }^2{\rho }_{11})/({\omega }^2{\rho }_{12})$. With that reading the two forms agree identically wherever ${\rho }_{12}$ is non-zero; at ${\rho }_{12}=0$ the corrected quotient is $0/0$ while Eq. (6.84) stays defined and gives ${\mu }_3=-{\rho }_{12}/{\rho }_{22}=0$, which is the value to use there. The printed form instead differs from Eq. (6.84) by the factor ${\rho }_{12}/{\rho }_{22}$, so it coincides with it only where that ratio is exactly 0 or exactly 1. With ${\rho }_{12}/{\rho }_{22}={\rho }_0/(\varphi {\rho }_{\text{eq}})-1$ those two cases ask for ${\rho }_{\text{eq}}={\rho }_0/\varphi$ and ${\rho }_{\text{eq}}={\rho }_0/(2\varphi )$, both real; the effective density of a lossy porous medium is complex, so neither is ever met. Verified on PDF page 132 (printed p. 123) of Allard & Atalla, Propagation of Sound in Porous Media 2e:2009, which carries both printed forms, and on the facing page for Eq. (6.80).
• Library behaviour: biot_waves implements Eq. (6.84) as printed, and test_shear_velocity_ratio_matches_the_corrected_second_printed_form checks it against the corrected Eq. (6.85) over four decades of frequency, and also asserts that the form exactly as printed disagrees.
• Status: unreported.

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Textbook, not a standard.

• Location: Sect. 11.3.3 (printed pp. 251-252), the fluid normal stress ${\sigma }_{33}^f$ of a poroelastic layer and the matrix $[\Gamma ]$ it feeds.

• The print: Eq. (11.48) reads

  $${\sigma }_{33}^f=\sum _i(Q+R{\mu }_i)(k_t^2+k_{i3}^2)\left\{-(A_i-A_i^{\prime })\cos (k_{i3}{x}_3)+j(A_i-A_i^{\prime })\sin (k_{33}{x}_3)\right\}$$

  and Table 11.1 writes $k_{i3}$ in the two columns that carry ${\mu }_1$, $D_1$ and $E_1$.

• The problem: two independent misprints in the same equation, plus a subscript slip in the table.

  • The coefficient of the symmetric amplitude $(A_i+A_i^{\prime })$ is missing: Eq. (11.48) attaches both terms to $(A_i-A_i^{\prime })$, which would leave the first and third columns of $[\Gamma ]$ with no ${\sigma }_{33}^f$ entry at all, contradicting Table 11.1, whose row 6 prints $-E_1\cos (k_{13}{x}_3)$ and $-E_2\cos (k_{23}{x}_3)$ in exactly those columns. The first term is $-(A_i+A_i^{\prime })\cos (k_{i3}{x}_3)$.
  • The sine carries $k_{33}$, the shear wave-number component, inside a sum over the two compressional waves $i=1,2$. It must be $k_{i3}$. Table 11.1 again gives the intended reading: its row 6 has $j{E}_1\sin (k_{13}{x}_3)$ and $j{E}_2\sin (k_{23}{x}_3)$, and zero in both shear columns, because a shear wave produces no dilatation and therefore no ${\sigma }_{33}^f$.
  • Table 11.1 prints the running subscript $k_{i3}$ in its first two columns, which belong to the first compressional wave alone: the ${\mu }_1$, $D_1$ and $E_1$ in the same columns make $k_{13}$ the only consistent reading.

• Evidence: the two readings above are forced by Table 11.1, which the same page declares to be the tabulation of Eqs. (11.37), (11.38) and (11.46)-(11.48). They are also what the stress-strain relation Eq. (11.41), ${\sigma }_{33}^f=R\mathrm{div}{u}_f+Q\mathrm{div}{u}_s$, gives when the displacement potentials of Eqs. (11.22)-(11.25) are differentiated directly. Verified on PDF page 257 (printed p. 251) and PDF page 258 (printed p. 252) of Allard & Atalla, Propagation of Sound in Porous Media 2e:2009, which carry Eq. (11.48) and the two Table 11.1 columns as printed.

• Library behaviour: the $[\Gamma ]$ of Table 11.1 is implemented with the corrected readings, and test_gamma_matches_the_field_rebuilt_from_the_potentials checks all thirty-six of its entries at three frequencies, three depths and three angles of incidence against the field rebuilt from Eqs. (11.22)-(11.28) without going through the table.

• Status: unreported.

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Textbook, not a standard.

• Location: Sect. 6.6.3, printed p. 129, the two glass-wool samples whose measured and predicted surface impedances are Figures 6.10 and 6.11.
• The print: the first sentence says the impedances are shown “for l = 10 cm and l = 5.4 cm”; two sentences later the peak of the second sample is placed at “860 Hz for l = 5.6 cm”, and the caption of Figure 6.11 says “l = 5.6 cm”.
• The problem: the two thicknesses cannot both be right.
• Evidence: textual, and only textual. Two printed statements carry 5.6 cm, the sentence about the 860 Hz peak and the independent caption of Figure 6.11, against one carrying 5.4 cm; a single slip in the opening sentence is the shorter explanation than the same slip made twice. The numbers do not settle it, and this entry does not claim they do. The book gives no peak-finding rule, and the answer follows the rule chosen:
  • Taking the peak as the maximum of $\text{Im}(Z_s)$, Eq. (6.107) on the fully specified Table 6.1 glass wool gives 863.5 Hz for 5.6 cm (+0.4 % against the printed 860) and 896.2 Hz for 5.4 cm (+4.2 %), which favours 5.6 cm. But the same rule puts the undisputed 10 cm sample at 480.0 Hz against its printed 470, a +2.1 % bias of the same size as the effect being resolved.
  • Taking the peak as the maximum of $|Z_s-Z_{s,\text{rigid}}|$, which is the departure the same paragraph describes (“close to each other, except around the peaks which are not predicted by the one-wave model”), the 10 cm sample lands at 469.2 Hz (-0.2 %) and both printed frequencies then come out of the pair (10 cm, 5.4 cm): 861.2 Hz for 5.4 cm (+0.1 %) against 831.0 Hz for 5.6 cm (-3.4 %). That rule favours 5.4 cm.
  • Scaling the 10 cm peak is no help either, and leans the other way from the conclusion: $470\times (10/5.4)=870\text{Hz}$ is 10 Hz from the published 860, $470\times (10/5.6)=839\text{Hz}$ is 21 Hz from it.
  • The agreement of “860 Hz” with “5.6 cm” is in any case partly circular, since both sit in the same clause: it tests that sentence against itself, not which of the two sentences is the misprint. Verified on PDF page 138 (printed p. 129) of Allard & Atalla, Propagation of Sound in Porous Media 2e:2009, on which the lone 5.4 cm and the 5.6 cm of the 860 Hz clause sit on the same page, and on PDF page 139 (printed p. 130) of the same edition for the Figure 6.11 caption, the second sentence carrying 5.6 cm.
• Library behaviour: recorded, with no effect on the implementation. test_impedance_peak_of_the_thin_layer_resolves_the_printed_thickness pins the 5.6 cm peak against the published 860 Hz under the $\text{Im}(Z_s)$ rule and checks that the 5.4 cm reading is the worse of the two under that rule.
• Status: unreported, and the weakest of the four entries here: the conclusion rests on the two-against-one reading of the printed page, not on a computation.

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Textbook, not a standard.

• Location: Sect. 6.5.4, printed p. 125, the one sentence of the book that quotes computed values of ${\mu }_b$ for the Table 6.1 glass wool.
• The print: “The ratio modulus $|{\mu }_b|$ of the velocities of the frame and the air for the frame-borne wave decreases from 1.0 at 50 Hz to 0.82 at 1500 Hz.”
• The problem: the two quoted values are the real part of ${\mu }_b$, not its modulus. ${\mu }_b$ is complex, and the sentence names the modulus explicitly.
• Evidence: on the fully specified Table 6.1 material the model gives ${\mu }_b(1500\text{Hz})=0.811+0.473j$. Its real part is 0.811, 1.1 % from the printed 0.82; its modulus is 0.939, 14.5 % away. Read as the real part, the sentence is right at both ends and describes a monotone decrease: $\text{Re}({\mu }_b)$ is 1.002 at 50 Hz and passes through 0.82 at 1467 Hz, 2.2 % from the printed 1500 Hz. Read as the modulus it is right at neither: $|{\mu }_b|$ is 1.002 at 50 Hz but rises to 1.008 by 400 Hz before turning over, and only reaches 0.82 at 2634 Hz, 76 % above the printed frequency. No admissible reading of the printed inputs closes that gap. With the loss factor at 0 or at 0.2, the viscous length halved or doubled, ${\Lambda }^{\prime }=2\Lambda$ in place of the printed $1.1\cdot 10^{-4}\text{m}$, the resistivity halved or doubled, the tortuosity at 1 or the Poisson coefficient at 0.3, $|{\mu }_b(1500)|$ moves only between 0.874 and 1.073. The closest of the eight, 0.874 at zero loss factor, is still 6.6 % from the printed 0.82, and it loses the 495 Hz branch crossing of the same section altogether; the only variant that keeps that crossing (${\Lambda }^{\prime }=2\Lambda$, 495.2 Hz) leaves $|{\mu }_b|$ at 0.937. Reading the sentence as $\text{Re}({\mu }_b)$ needs no variant at all. Verified on PDF page 134 (printed p. 125) of Allard & Atalla, Propagation of Sound in Porous Media 2e:2009, which carries the sentence and its 0.82.
• Library behaviour: biot_waves computes ${\mu }_b$ from Eq. (6.71) as printed. The conformance row and test_frame_borne_velocity_ratio_matches_the_two_published_values are written against $\text{Re}({\mu }_b)$, and say so.
• Status: unreported.

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• Location: Appendix B, section B7.1.1, the deceleration $a$ defined under Eq. (B-41), on the page that carries Eq. (B-40) and Eq. (B-41).
• The print: $a=k^2\left({\left(\left({Pt1(\mathrm{NextSeg})}_{TAS}-w\right)/\cos \gamma \right)}^2-{\left(\left({Point1}_{TAS}-w\right)/\cos \gamma \right)}^2\right)/\left(2\left(Point1\_Height-Pt1(\mathrm{NextSeg})\_Height\right)/\sin \gamma \right)$, that is both ground speeds divided by $\cos \gamma$ over twice the slant length of the segment.
• The problem: the descent slope is counted twice. The mean deceleration along the flight path is the change in the square of the along-path speed over twice the path length; the printed expression converts the speeds to along-path values and uses a path length that is already the slant one, so it overstates $|a|$ by $1/{\cos }^2\gamma$. The 4th edition’s Eq. (B-21) is self-consistent, and the denominator is not what changed: it reads $2\cdot \Delta s/\cos \gamma$ with $\Delta s$ “the ground distance covered”, which is the same slant length the 5th edition writes as $2\left(Point1\_Height-Pt1(\mathrm{NextSeg})\_Height\right)/\sin \gamma$. What changed is the numerator. The 4th edition’s Eq. (B-22) defines the speeds it divides as groundspeeds, $V=V_C\cos \gamma /\sqrt{\sigma }-w$, that is the true airspeed resolved into the horizontal plane, so dividing each by $\cos \gamma$ correctly restores an along-path speed. The 5th edition feeds Eq. (B-41) the profile points’ own $\mathrm{TAS}$, which is along-path already, and kept the division. Doc 29’s own reference results decide it: of the twelve points of Volume 3 Part 2 case 2D, flown entirely at that step type, nine are reached by the deceleration. The plain ground speeds reproduce the tabulated thrust at every one of the twelve, worst deviation 0.047 lb, while the printed divided speeds fall short at all nine, by 6.05, 5.47, 4.02, 3.81, 4.56, 4.45, 0.29, 6.35 and 6.41 lb in profile order: always low, and never within the workbook’s own 0.05 lb of printed precision. The drag term beside it does keep the $\cos \gamma$ the same equation prints, which the same points confirm to the same 0.05 lb.
• Evidence: reproduction of Volume 3 Part 2 sheet D1-(Arrival_Results) case 2D under each reading. Verified on PDF page 104 (printed p. B-31) of ECAC.CEAC Doc 29, 5th ed., Volume 2: Technical guide, which carries Eq. (B-40), Eq. (B-41) and the deceleration under it, and on PDF page 90 (printed p. B-15) of ECAC.CEAC Doc 29, 4th edition, Volume 2, which carries Eq. (B-21) and, immediately under it, the Eq. (B-22) that defines its $V_1$ and $V_2$ as groundspeeds and so decides the reading.
• Library behaviour: flight_performance computes the deceleration from the plain ground speeds over the slant length, and the helper’s docstring carries the departure and the numbers above. test_arrival_case_reproduces_every_profile_point pins all 124 arrival points, and the conformance row ECAC Doc 29 Appendix B approach thrust pins the descent thrust of case 2A.
• Status: unreported.

• Location: Appendix B, section B6.1.1, the average acceleration $a$ defined under Eq. (B-18).
• The print: ”$a$ is the average acceleration (ft/s${}^2$) along the runway, equal to: $a={\left(V_C/\sqrt{\sigma }\right)}^2/\left(2\cdot s_{TOw}\right)$”, with ”$V_C$ is the Calibrated Airspeed (kt) at Point2” and $s_{TOw}$ in feet on the same page.
• The problem: the expression is declared in ft/s${}^2$ and evaluates in kt${}^2$/ft. The missing factor is $k^2=1.68781^2=2.8487$, the square of the knots-to-feet-per-second constant Doc 29 fixes in B2.2 and carries explicitly in Eq. (B-24) and Eq. (B-41), which build accelerations out of the same kind of expression. It is not cosmetic: $a$ enters only through $a/(a-g{G}_R)$, so understating it by 2.85 overstates the gradient correction, and at a 1 % upslope with $V_{CTO}=162.65$ kt and $s_{TOw}=4900$ ft the dimensionally correct 7.69 ft/s${}^2$ gives a factor of 1.0437 against the literal reading’s 1.1353: 8.8 % of take-off distance. The 4th edition carries the same omission, so it is inherited rather than introduced, and prints ${\left(V_C\sqrt{\sigma }\right)}^2$ where the 5th prints ${\left(V_C/\sqrt{\sigma }\right)}^2$; only the 5th edition’s placement is a speed the aeroplane has, since $V_C/\sqrt{\sigma }$ is the true airspeed of Eq. (B-7).
• Evidence: dimensional analysis against the same document’s Eq. (B-24) and Eq. (B-41). Verified on PDF page 90 (printed p. B-17) of ECAC.CEAC Doc 29, 5th ed., Volume 2: Technical guide, and, for the inherited half, on PDF page 86 (printed p. B-11) of ECAC.CEAC Doc 29, 4th edition, Volume 2, where the same definition sits under Eq. (B-11) and reads ${\left(V_C\cdot \sqrt{\sigma }\right)}^2/\left(2\cdot s_{TOw}\right)$, ft/s${}^2$. This one cannot be arbitrated against the reference results: Volume 3 Part 2’s departure case sheet C8-(Departure_Cases) has no runway-gradient column, so all 17 reference cases are flown at $G_R=0$, where Eq. (B-18) is the identity.
• Library behaviour: flight_performance restores $k^2$ and takes the 5th edition’s $\sqrt{\sigma }$ placement; the helper’s docstring states both departures and that no reference case can detect either.
• Status: unreported.

• Location: Appendix B, section B6.1.2, the mid-step corrected net thrust $\overline{CNT}$ defined under Eq. (B-21), in the branch that computes it from Eq. (B-12), that is for every aeroplane the propeller coefficient table carries. B4.1 and B4.2 split the turboprops between them without stating a rule, so this is not the same set as “the turboprops”: of the 20 in ANP v2.3, 11 sit in the propeller table and reach Eq. (B-12), the other 9 sit in the jet table and reach Eq. (B-9), and the 8 piston aeroplanes are all in the propeller table.
• The print: $\overline{CNT}$ “is the Corrected Net Thrust of the aircraft when being located at mid-step, i.e. at the altitude $Alt=E_{Apt}+\left(\mathrm{Point}1\_Height+\mathrm{Point}2\_Height\right)/2$”, and then, under “In the case of Eq. B-12,”, $V_T=\sqrt{0.5\left({\left(\mathrm{Point}2\_TAS\right)}^2+{\left(\mathrm{Point}1\_TAS\right)}^2\right)}$, the root mean square of the two endpoint true airspeeds.
• The problem: the speed contradicts the altitude named one line above it. A Climb step is flown at a held calibrated airspeed, so the true airspeed at the mid-step altitude is fixed and is $V_C/\sqrt{\sigma }$ evaluated at the mid-step $\sigma$ (Eq. B-7); the root mean square of the two endpoint values is a different number. The two branches of the same list therefore describe two different aeroplanes at the one point they both call mid-step: the jet branch prints $V_C=\mathrm{Point}2\_TAS\cdot \sqrt{{\sigma }_{Point2}}$, which is the step’s own held calibrated airspeed and so places the aeroplane at $V_C/\sqrt{\sigma }$ halfway up, while the Eq. (B-12) branch places it at the root mean square of the ends. The mean also reads as transplanted. Section B6.1.3, for the Accelerate step, is built on exactly this root mean square and is self-consistent about it, giving both branches the same $\overline{V_T}=\sqrt{\left(V_{T2}^2+V_{T1}^2\right)/2}$ and converting it for the jet form with the mid-step $\sqrt{{\sigma }_{Alt}}$; B6.1.2 keeps the Eq. (B-12) line but replaces the jet line with a Point 2 quantity, and only one of the two survives the substitution. Of the candidates the printed one is the largest: at constant $V_C$ the true airspeed rises convexly with altitude, so the root mean square exceeds the arithmetic mean, which exceeds the mid-altitude value. Eq. (B-12) makes thrust inversely proportional to $V_T$, so the printed speed understates the mid-step thrust, understates $\sin \gamma$ and lays the climb down long.
• Evidence: reproduction of Volume 3 Part 2 sheet D2-(Departure_Results) under each reading. The four turboprop departure cases are the only reference data that reach this branch, and they are unanimous. On case 56 the final profile point is printed at 400814.3 ft: the mid-step altitude reading lands it 0.001 ft away, the arithmetic mean 323.944 ft long and the printed root mean square 544.944 ft long, against the 0.15 ft the departure distances are otherwise matched to. Cases 8, 28 and 68 put the same final point 172.333, 223.003 and 544.944 ft long under the printed reading and 102.535, 132.673 and 323.944 ft long under the arithmetic mean, always long and never near the printed precision; the mid-step altitude reading is within 0.049 ft of every point of all four cases, worst case 28. The departure grows with the height of the step, as a convexity error must: on case 8 the printed reading puts $V_T$ 0.0225 kt above the mid-step value on the 1500 ft climb and 0.1066 kt above it on the 2500 ft one. Verified on PDF page 92 (printed p. B-19) of ECAC.CEAC Doc 29, 5th ed., Volume 2: Technical guide, which carries the mid-step altitude sentence, the jet branch’s $V_C$ and the Eq. (B-12) branch’s $V_T$ on the one page, and on PDF page 95 (printed p. B-22) of the same document for the B6.1.3 pair the Eq. (B-21) line appears to be drawn from.
• Library behaviour: flight_performance evaluates the propeller form at the true airspeed the aeroplane has at the mid-step altitude, and the Climb-step helper’s comment quotes the printed expression, says the model departs from it and points here. test_departure_case_reproduces_every_profile_point pins all 190 departure points, four cases of which are flown on Eq. (B-12).
• Status: unreported. Of the three Appendix B departures recorded here this is the one the reference results decide most sharply, and the only one that changes a shipped profile.

• Location: clause 5.2, Table V “Tolerance limits on relative response levels for sound at random incidence measured on an instrument’s calibration range”, 20 Hz row, type 2 column (printed p. 6).
• The print: the cell reads ”+ 3”, with no second term. Its column neighbours at 10, 12.5 and 16 Hz read ”+ 5, − ∞”, and the type 0 and type 1 cells of its own row read ”± 2” and ”± 2.5”.
• The problem: the table has one notation for an upper-only limit, a pair ”+ n, − ∞”, and it is used three rows above this cell in the same column. This cell uses neither that notation nor the ”± n” of its row, so it is either a limit written in a form the table uses nowhere else or a ”±” whose bar failed to print. IEC 651:1979 Table V, of which this table is the US counterpart and with which the type 2 column agrees at all thirty-three other rows, prints “±3” at exactly this cell. The intended reading is ±3 dB.
• Evidence: the cell and its column neighbours, read on PDF page 16 (printed p. 6) of ANSI S1.4-1983, against the same cell on PDF page 10 (printed p. 8, marked “[IEC page 19]”) of BS 5969:1981, the identical British adoption of IEC 651:1979.
• Library behaviour: _ANSI_S14_TABLE5_12 in weighting_compliance.py and its reference_data twin carry −3 dB as the 20 Hz type 2 lower limit, the stricter of the two readings, with the note beside them. test_b_masks_match_reference_data pins the two transcriptions to each other. No shipped verdict moves: the realized B weighting sits 0,05 dB below nominal at 20 Hz and clears either reading.
• Status: unreported.

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• Location: Annex E (informative), E.4.2.6.2 “Excess sound pressure, measurement distance effect, ${\delta }_r$”, the sentence giving the directly radiated pressure and the two sentences that build on it.
• The print: “the directly radiated pressure is approximately $L_{p,\mathrm{direct}}=L_W+10\lg (2\pi r^2/r_0^2)$ dB. Rearranging Equation (A.1) using $L_{p,\mathrm{direct}}$, gives $L_{p(\mathrm{RSS}),r}=L_{p,\mathrm{direct}}+\Delta L_f-3$ dB”, and the sensitivity coefficient that follows, $c_r=10^{-0,1(\Delta L_f-3\mathrm{dB})}8,7/r$.
• The problem: the direct field of a source over a reflecting plane falls with distance, $L_{p,\mathrm{direct}}=L_W-10\lg (2\pi r^2/r_0^2)$ dB; the printed plus sign makes it grow. The two sentences that follow hold only with the minus sign. Substituting $L_{p,\mathrm{direct}}=L_W-20\lg (r/r_0)-8$ dB into Eq. (A.1) rearranged, $L_{p(\mathrm{RSS}),r}=L_{W(\mathrm{RSS})}+\Delta L_f-11-20\lg (r/r_0)$ dB, gives the printed $L_{p,\mathrm{direct}}+\Delta L_f-3$ dB, whereas the plus sign gives $L_{p,\mathrm{direct}}+\Delta L_f-19\mathrm{dB}-40\lg (r/r_0)$; and the $8,7/r$ of the sensitivity coefficient is $20/(r\ln 10)$, the derivative of $-20\lg r$, so the printed $c_r$ is the derivative of the minus-sign form. A sign misprint in an informative annex.
• Evidence: the three consecutive sentences of E.4.2.6.2 read against each other and against Eq. (A.1). Verified on PDF page 47 (printed p. 38) and PDF page 30 (printed p. 21) of BS EN ISO 3747:2010.
• Library behaviour: the Annex E uncertainty budget is not modelled; the library evaluates Eq. (A.1) as printed (excess_sound_pressure_level), which the misprint does not touch. No number changes.
• Status: unreported.

• Location: Annex E (informative), E.4.2.5 “Radiation impedance correction, $C_2$”, the sentences that size $u_{C_2}$.
• The print: “For altitudes less than 500 m above sea level, no meteorological correction is required. At 120 m altitude and 23 °C, the correction is 0 dB and at 500 m altitude, the correction is 0,6 dB. Assuming a triangular distribution for this uncertainty, the standard deviation is $u_{C_2}=0,6/\sqrt{6}=0,3$ dB.”
• The problem: the normative Annex C defines the correction as $C_2=-10\lg (p_{\mathrm{s}}/p_{\mathrm{s},0})+15\lg [(273,15+\theta )/{\theta }_{\mathrm{ref}}]$ with the static pressure of Eq. (C.2), $p_{\mathrm{s}}=p_{\mathrm{s},0}(1-a{H}_{\mathrm{a}}{)}^b$. At 23 °C that gives 0,07 dB at 120 m ($p_{\mathrm{s}}$ = 99,89 kPa, of which the pressure term $-10\lg (p_{\mathrm{s}}/p_{\mathrm{s},0})$ is 0,06 dB) and 0,26 dB at 500 m ($p_{\mathrm{s}}$ = 95,46 kPa), not the printed 0,6 dB, and the arithmetic printed after it does not close either: $0,6/\sqrt{6}=0,245$, printed 0,3. No altitude below which “no meteorological correction is required” appears in Annex C. The informative example is inconsistent with the normative annex it cites.
• Evidence: recomputation of Eq. (C.2) and $C_2$ from the printed constants ($a$ = 2,2560 × 10⁻⁵ m⁻¹, $b$ = 5,255 3, $p_{\mathrm{s},0}$ = 1,013 25 × 10⁵ Pa, ${\theta }_{\mathrm{ref}}$ = 296 K). Verified on PDF page 46 (printed p. 37) and PDF page 36 (printed p. 27) of BS EN ISO 3747:2010.
• Library behaviour: implements Annex C as printed: static_pressure_from_altitude evaluates Eq. (C.2) and the result’s c2 the correction, so a site at 500 m gets the 0,26 dB the annex gives. The Annex E budget is not modelled. Pinned by test_static_pressure_from_altitude_eq_c2 in tests/emission/test_sound_power_in_situ.py and by the conformance check “ISO 3747:2010 Eq. C.2”.
• Status: unreported.

• Location: Annex E (informative), Table E.2 “Uncertainty budget for determinations of ${\sigma }_{R0}$…”, the sensitivity-coefficient cell of the ${\delta }_r$ (measurement distance) row.
• The print: $c_i=10^{-0,1(L_f-3)}8,7/r$.
• The problem: the quantity in the exponent is the excess of sound pressure level over the free field, $\Delta L_f$ of Eq. (A.1), not a level $L_f$; no quantity called $L_f$ is defined anywhere in the standard. E.4.2.6.2, which derives this very coefficient, prints it as $c_r=10^{-0,1(\Delta L_f-3\mathrm{dB})}8,7/r$, and its worked extreme ($\Delta L_f$ = 7,1 dB, $r$ = 6 m) reproduces the 0,6 quoted there only with the excess in the exponent ($10^{-0,41}\times 8,7/6=0,564$). The delta was dropped in the table.
• Evidence: the table cell read against the text that derives it, verified on PDF page 44 (printed p. 35) and PDF page 47 (printed p. 38) of BS EN ISO 3747:2010. Table E.2 is specific to this part: the corresponding row of ISO 3744:2010 carries the free-field coefficient $c_S=8,7/r$ with no excess factor at all, so the slip is not inherited from the family.
• Library behaviour: the Annex E uncertainty budget is not modelled, and the excess itself is evaluated from Eq. (A.1) by excess_sound_pressure_level. No number changes.
• Status: unreported.

• Location: Annex E (informative), Table E.2 “Uncertainty budget for determinations of ${\sigma }_{R0}$…”, the sensitivity-coefficient cell of the ${\delta }_{\mathrm{mic}}$ (sampling) row.
• The print: $c_i=0,5$.
• The problem: E.4.2.6.3, the clause that derives that very row, prints the opposite together with its reason: “Sampling directly affects the total uncertainty so $c_{\mathrm{mic}}=1$”. The budget of E.4.2.12 sides with the clause and not with the table: its sixth term is $0,7^2$, which is the 0,7 dB contribution E.4.2.6.3 quotes taken at $c_{\mathrm{mic}}=1$. The neighbouring row settles that 0,5 is no blanket convention for instrument rows, because E.4.2.7 sets $c_{\mathrm{slm}}=0,5$ and earns it: repeated readings on one meter let the systematic errors cancel, which halves the coefficient, and the clause then reproduces the budget’s own term ($0,5\times 0,5=0,25$ dB, quoted there as 0,3 dB for each of the two sources, and $\sqrt{0,3^2+0,3^2}=0,42$ dB, the 0,4 that E.4.2.12 sums). The sampling row carries no such derivation, and cannot carry one: ${\delta }_{\mathrm{mic}}$ is defined on the difference $\Delta L_{p(\mathrm{ST}-\mathrm{RSS})}^{\prime }=L_{p(\mathrm{ST})}^{\prime }-L_{p(\mathrm{RSS})}^{\prime }$, which already spans both sources, so there is no second contribution to halve. The family agrees with the clause: the corresponding ${\delta }_{\mathrm{mic}}$ row of Table H.2 in ISO 3744:2010 carries $c_i=1$, and its H.4.2.9 prints $c_{\mathrm{mic}}=1$ as well.
• Evidence: the table cell, the clause that derives it and the budget that sums it, read on PDF pages 44, 47 and 50 (printed pp. 35, 38 and 41) of BS EN ISO 3747:2010; the family comparison on PDF pages 79 and 82 (printed pp. 70 and 73) of BS EN ISO 3744:2010.
• Library behaviour: the Annex E uncertainty budget is not modelled. The reproducibility the library reports is the tabulated ${\sigma }_{R0}$ of Table 2, read by accuracy grade. No number changes.
• Status: unreported.

• Location: Annex E (informative), E.4.2.3 “Sound pressure measurement repeatability, $\overline{L_{p(\mathrm{ST})}^{\prime }}$”, the sentence introducing the sensitivity coefficient $c_{L_{p(\mathrm{ST})}^{\prime }}$.
• The print: “It is obtained from the derivative of $L_{W\mathrm{ref},\mathrm{atm}}$ [Equation (E.1)], with respect to $\overline{L_{p(\mathrm{ST})}^{\prime }}$.”
• The problem: Equation (E.1) is the standard deviation of the operating and mounting conditions, ${\sigma }_{\mathrm{omc}}=\sqrt{\frac{1}{N-1}\sum (L_{p,j}-L_{p\mathrm{av}}{)}^2}$, which contains no $L_{W\mathrm{ref},\mathrm{atm}}$ and cannot be differentiated with respect to $\overline{L_{p(\mathrm{ST})}^{\prime }}$. The model that carries $L_{W\mathrm{ref},\mathrm{atm}}$ is Equation (E.2), printed on the facing page, and differentiating it (with $K_1$ substituted from Eq. 7) does give the printed $c_{L_{p(\mathrm{ST})}^{\prime }}=1+1/(10^{0,1\Delta L_p}-1)$. A cross-reference misprint: (E.1) for (E.2).
• Evidence: verified on PDF page 45 (printed p. 36), which carries the sentence and the coefficient, against PDF page 41 (printed p. 32) for Eq. (E.1) and PDF page 42 (printed p. 33) for Eq. (E.2), of BS EN ISO 3747:2010. ISO 3741:2010 prints the same coefficient as “the derivative of $L_W$ with respect to $L_{p(\mathrm{ST})}^{\prime }$” with no equation number, so the wrong number is this part’s own.
• Library behaviour: the Annex E uncertainty budget is not modelled, so no library number depends on it. Recorded so that a future reader chasing the derivation is not sent to the wrong equation.

• Location: Annex A, Table A.5, “Values of coefficients $a_i$ for the determination of the combined mean flow velocity and modal correction $C_{3,4}$ of the sampling tube for duct diameters 0,8 m $\le d<$ 1,25 m”, row 5 000 Hz, column $a_3$.
• The print: $-,24\times 10^{-05}$: a minus sign, a space, a decimal comma and two digits, with no digit before the comma. Every other cell of the twelve coefficient tables of Annexes A, H and I prints one digit before the comma.
• The problem: the coefficient cannot be read from the document, and the row is inside the normative range of the standard (5 000 Hz, $|U|\le 40$ m/s). The $a_3$ of the same band in the two neighbouring tables is $-1,17\times 10^{-5}$ (Table A.4, 0,5 m to 0,8 m) and $-1,27\times 10^{-5}$ (Table A.6, 1,25 m to 2 m), which brackets $-1,24\times 10^{-5}$; a leading digit of 2 or more would move $C_{3,4}$ at 40 m/s by 0,64 dB per unit of the digit ($a_3{U}^3$ with $U^3=6,4\times 10^4$), which no neighbouring band or table supports.
• Evidence: the cell as printed. PDF page 39 (printed p. 29) of ISO 5136:2003, against the same cell of Table A.4 on PDF page 38 (printed p. 28) and of Table A.6 on PDF page 40 (printed p. 30).
• Library behaviour: reads $-1,24\times 10^{-5}$, the value the neighbours bracket, in _TABLE_A5 of sound_power_in_duct.py. The table’s comment and test_table_a5_5000_hz_reads_the_missing_digit_as_one in tests/emission/test_sound_power_in_duct.py say that it is a reading and not the print; a copy of the standard in which the digit survived would settle it.
• Status: unreported.

• Location: the first sentence of Annex D, and the sentence of Annex H and of Annex I that introduces their coefficient tables.
• The print: “For $d$ = 0,5 m, the values of the coefficients $a_i$ for the calculation of $C_{3,4}$ according to Equation (3) are given in Table A.4” (Annex D); “Values for the coefficients $a_i$ necessary to compute the mean flow velocity-modal corrections $C_{3,4}$ according to Equation (3) are given in Tables H.1 to H.3” (Annex H) and ”… in Tables I.1 to I.3” (Annex I).
• The problem: Equation (3) is the cut-on frequency of the first cross mode, $f_{1,0}=0,586(c/D)\sqrt{1-(U/c{)}^2}$, in the definition of 3.10. The polynomial in $U$ whose coefficients the tables hold is Equation (7) of clause 5.3.3.4. The same wrong number is printed three times.
• Evidence: PDF pages 45, 64 and 68 (printed pp. 35, 54 and 58) of ISO 5136:2003, against Equation (3) on PDF page 16 (printed p. 6) and Equation (7) on PDF page 28 (printed p. 18).
• Library behaviour: evaluates Equation (7); flow_modal_correction cites it. No number changes.
• Status: unreported (cross-reference defect, no numerical consequence).

• Location: Annex B, clause B.2, “Comparative procedure using a microphone fitted with a nose cone and a microphone fitted with a sampling tube”, Step 4.
• The print: “Check whether the difference between the circumferentially averaged sound pressure levels obtained with the nose cone and the sampling tube ($\overline{L_{p\mathrm{NC}}}-\overline{L_{p\mathrm{ST}}}$) is smaller than or equal to the maximum allowable difference $\Delta L_{\max }$ given in Table C.1.”
• The problem: Table C.1 is the A-weighting $C_j$ of Annex C and holds no $\Delta L_{\max }$. The table of the maximum allowable difference against the turbulence noise suppression $\Delta L_{\mathrm{t}}$ of the sampling tube is Table B.1, on the page after the step, and the paragraph two above the steps already sends the reader to it (“see Table B.1”).
• Evidence: PDF page 41 (printed p. 31) of ISO 5136:2003, with Table B.1 on PDF page 42 (printed p. 32) and Table C.1 on PDF page 44 (printed p. 34).
• Library behaviour: the signal-to-noise procedure of Annex B is a qualification of the measurement, not a term of $L_W$, and is not implemented. No change was needed.
• Status: unreported (cross-reference defect, no numerical consequence).

• Location: Annex B, clause B.1, “General”, the first sentence.
• The print: “Two procedures for the determination of the combined mean flow velocity are given in B.2 and B.3.”
• The problem: the annex is titled “Determination of the signal-to-noise ratio of sound vs. turbulent pressure fluctuation in the test duct”, and B.2 and B.3 determine that ratio; nothing in the annex determines a “combined mean flow velocity”, a phrase that is a fragment of the “combined mean flow velocity and modal correction” of clause 5.3.3.4. The sentence also counts two procedures where the annex, by the coherence method it closes with, gives three.
• Evidence: PDF page 41 (printed p. 31) of ISO 5136:2003, the annex title and the sentence on the same page, and the coherence procedure on PDF page 43 (printed p. 33).
• Library behaviour: Annex B is not implemented; nothing to change.
• Status: unreported (wording defect).

• Location: clause 7.4, the NOTE that follows the outlet-duct rule for large fans in installation category D.
• The print: “The hydraulic diameter of the fan outlet area, $S_{\mathrm{f}2}$, is given by $D_{\mathrm{h}}=\sqrt{S_{\mathrm{f}2}/\pi }$”.
• The problem: $\sqrt{S/\pi }$ is the radius of the circle of area $S$; its diameter is $\sqrt{4S/\pi }=2\sqrt{S/\pi }$. Followed as printed, the “2 $D_{\mathrm{h}}$” the clause asks the outlet duct to be is one equivalent diameter long, not two, and whether the rule intended is two diameters or two radii cannot be settled from the document.
• Evidence: PDF page 33 (printed p. 23) of ISO 5136:2003.
• Library behaviour: the duct lengths of clauses 5.2 and 7.4 are facility geometry and are not computed; nothing to change.
• Status: unreported.

• Location: Annex A, Table A.2, “Values of coefficients $a_i$ for the determination of the combined mean flow velocity and modal correction $C_{3,4}$ of the sampling tube for duct diameters 0,2 m $\le d<$ 0,3 m”, the header row of the coefficient columns, tenth column.
• The print: an italic $a$, an italic 9 on the baseline and a subscript 0, between an $a_8$ and an $a_{10}$ of the same row that both carry their index as a subscript.
• The problem: a stray subscript zero on a column that is $a_9$. The same column is headed $a_9$ in Tables A.1 and A.3 to A.6, the NOTE under every one of them sums $a_i{U}^i$ from $i=0$ to $i=10$ over the eleven columns the row has, and the single cell this one holds, the $4,09\times 10^{-14}$ of the 20 000 Hz row, is the coefficient of $U^9$: an $a_{90}$ would have no place in that sum at all.
• Evidence: PDF page 36 (printed p. 26) of ISO 5136:2003, against the header row of Table A.1 on PDF page 35 (printed p. 25).
• Library behaviour: the column is read as $a_9$. _TABLE_A2 in sound_power_in_duct.py carries the 20 000 Hz row as the ten coefficients $a_0$ to $a_9$, and test_table_a2_20_khz_row_reads_the_last_column_as_a9 in tests/emission/test_sound_power_in_duct.py multiplies the row out. No coefficient value changes.
• Status: unreported (typographic, no numerical consequence).

• Location: Annex A, Table A.6, ”… for duct diameters 1,25 m $\le d\le$ 2 m”, row 16 000 Hz, column $a_1$.
• The print: $4,52\times \times 10^{-01}$, two multiplication signs where every other cell prints one.
• The problem: typographic only; the mantissa and the exponent are legible and the value is $4,52\times 10^{-1}$, in line with the $4,51\times 10^{-1}$ of Table A.5 and the $4,52\times 10^{-1}$ of Table I.1 at the same band. The row is in the informative range above 10 kHz.
• Evidence: PDF page 40 (printed p. 30) of ISO 5136:2003.
• Library behaviour: $4,52\times 10^{-1}$ in _TABLE_A6 of sound_power_in_duct.py.
• Status: unreported (typographic, no numerical consequence).

• Location: Annex I, Table I.2, ”… for duct diameters 3,55 m $\le d\le$ 5 m”, the continuation page, row 20 000 Hz, columns $a_8$ and $a_9$.
• The print: $a_8=-5,88\times 10^{-10}$ and $a_9=2,25\times 10^{-10}$.
• The problem: at $U$ = 40 m/s the printed $a_9$ alone contributes $2,25\times 10^{-10}\times 40^9\approx 5,9\times 10^4$ dB to $C_{3,4}$, which no correction can be. The same row of the neighbouring tables prints $a_8=-5,90\times 10^{-12}$ and $a_9=2,25\times 10^{-13}$ (Table I.1) and $a_9=2,25\times 10^{-13}$ (Table I.3), so the exponents are $-12$ and $-13$ and the print is short by two and three decades. Annex I is informative and the row is in the informative range above 10 kHz.
• Evidence: PDF page 72 (printed p. 62) of ISO 5136:2003, against the same row of Table I.1 on PDF page 70 (printed p. 60) and of Table I.3 on PDF page 74 (printed p. 64).
• Library behaviour: the informative Annexes H and I are outside the scope the standard states for itself (0,15 m to 2 m) and are not implemented; a duct above 2 m is refused. Recorded so that an implementation of Annex I does not carry the exponents as printed.
• Status: unreported.

• Location: Annex C (informative), Table C.1, “A-weighted octave-band sound pressure levels, $L_{p,\mathrm{A}f(k)i}$, from Table 2”, PDF page 17 (printed p. 11), against the normative Table 2 it names, PDF page 11 (printed p. 5).
• The print: the two tables carry the same eight reference noises over the same seven octave bands, and seven of the eight rows agree digit for digit. The sixth reads 82,0 / 89,3 / 93,3 / 95,6 / 93,0 / 90,1 / 83,0 in Table 2 and 82,0 / 89,4 / 93,5 / 95,6 / 93,0 / 90,1 / 83,0 in Table C.1. The 250 Hz and 500 Hz cells differ; nothing else does.
• The problem: Table C.1 states in its own caption that it comes from Table 2, so one of the two is wrong, and the annex’s own results say which. Formula (15) applied to the sixteen attenuation values of Table A.1 with Table 2’s row reproduces all sixteen $PN{R}_{j6}$ of Table C.2 exactly; with Table C.1’s row, thirteen of the sixteen fall 0,1 dB short. Table 2 is therefore the reading the worked example was computed from, and it is also the normative one, Table C.1 being an informative reprint. An implementer who takes the reference spectra from Annex C, where they sit next to the worked example, gets a protector’s $H$ and $M$ values a tenth of a decibel low.
• Evidence: Formula (15), PDF page 11 (printed p. 5), evaluated on Table A.1, PDF page 15 (printed p. 9), against the sixth row of Table C.2, PDF page 18 (printed p. 12), all of ISO 4869-2:2018.
• Library behaviour: HML_REFERENCE_NOISES carries Table 2. The test suite computes the same row from Table C.1’s values and asserts that it misses thirteen of the printed sixteen, so the two readings can never be silently swapped.
• Status: unreported.

• Location: printed folio 40 (PDF page 40), Section 6.4 “Verzweigungen” / “Junctions”, the sentence directly under Equation (35).
• The print: the German column reads “Diese in Bild 27 dargestellte Senkung des Schallleistungspegels ist frequenzunabhängig.” The English column of the same page, translating the same sentence, reads “This sound power level reduction shown in Figure 27 depends on the frequency.”
• The problem: the two say opposite things, and the German is the authoritative one: the cover of every VDI guideline states that the German version shall be taken as authoritative and that no guarantee is given for the English translation. The German is also the one the rest of the document agrees with. Figure 27 on the same page plots $\Delta L_W$ against the cross-section ratio $S_1/\sum S_{1,2,3}$ alone and carries no frequency axis; Equation (35) itself, $\Delta L_W=|10\lg (S_1/{\sum }_i{S}_i)|$, contains no frequency; and the worked example of VDI 2081 Blatt 2:2005-05 prints a junction’s level reduction as a single number rather than as an octave spectrum, in each of its three junctions (Table 1, elements 3, 7 and 16, printed folios 13 and 15: $5,6$, $4,8$ and $3,0$ dB).
• The likely mechanism: the negating prefix of “frequenzunabhängig” is absent from the translation, which turns “independent of the frequency” into its opposite. Nothing else in the sentence differs.
• Consequence: a reader working from the English column alone would look for a frequency dependence that neither the equation nor the figure has, and might conclude that the guideline is incomplete rather than that the sentence is mistranslated.
• Evidence: the two columns of the same printed page read against each other; Figure 27 on that page; Equation (35) above it; and the three junction rows of the worked example in Blatt 2. Verified on PDF page 40 (printed p. 40) of VDI 2081 Blatt 1:2001-07 and PDF pages 13 and 15 (printed pp. 13 and 15) of VDI 2081 Blatt 2:2005-05.
• Library behaviour: split_loss with model="vdi2081" returns one value for the junction, the German reading, and reproduces all three printed junctions of the worked example.
• Status: unreported. Both prints are superseded (Blatt 1:2022-04 and Blatt 2:2022-10) and neither successor is held, so whether the translation was corrected is not known here.

• Location: Table 1, printed folio 12 (PDF page 12), element 2, the splitter silencer: the rows “Hydr. Durchmesser $d_{\mathrm{h}}$ (m)” and “Strouhalzahl $St$”.

• The print: $d_{\mathrm{h}}=0,171$ m, and the eight Strouhal numbers $0,9$, $1,7$, $3,4$, $6,8$, $13,5$, $27,0$, $54,0$ and $108,0$ over the octaves 63 Hz to 8 kHz, for a clear gap $s=0,100$ m, a splitter height $H=0,600$ m and a gap speed $v=14,81$ m/s.

• The problem: the two rows disagree. VDI 2081 Blatt 1 Section 7.2.4.2 defines $St=f_{\mathrm{m}}{d}_{\mathrm{h}}/v_{\mathrm{i}}$, so the printed $d_{\mathrm{h}}$ and the printed $St$ determine each other. With the printed $0,171$ m the eight numbers would be $0,73$, $1,45$, $2,89$, $5,79$, $11,57$, $23,15$, $46,29$ and $92,59$: not one of them rounds onto the printed row. With $d_{\mathrm{h}}=2s=0,200$ m they come out as $0,851$, $1,688$, $3,376$, $6,752$, $13,504$, $27,009$, $54,018$ and $108,035$, which round onto all eight.

  Both values are defensible as a hydraulic diameter, which is why this is an internal inconsistency rather than a wrong number: $4A/P$ for a $0,100$ m by $0,600$ m gap is $0,171$ m, while the parallel-plate limit that a long narrow gap tends to is $2s=0,200$ m. The table prints the first and computes with the second.

• Consequence: following the printed $d_{\mathrm{h}}$ reproduces neither the Strouhal row nor the flow-noise spectrum beneath it. With $2s$ the whole element falls out to the last printed decimal: $L_{\mathrm{WA}}=52$ dB from Equation (49) and the eight octave levels $62,7$ down to $35,6$ dB from Equations (46), (50) and (51), the worst of them 0,046 dB from its printed cell.

• Evidence: the two rows of the same printed element read against Section 7.2.4.2 of Blatt 1 (printed folio 53); both candidate diameters evaluated over the eight octaves; and the flow-noise spectrum recomputed from each. Verified on PDF page 12 (printed p. 12) of VDI 2081 Blatt 2:2005-05 and PDF page 53 (printed p. 53) of VDI 2081 Blatt 1:2001-07.

• Library behaviour: silencer_self_noise with model="vdi2081" takes the clear gap and uses $2s$, so it reproduces the worked example. The docstring says which of the two it takes.

• Status: unreported. Both prints are superseded and neither successor is held.

• Location: Table 1, printed folio 12 (PDF page 12), element 2, the box reading “Tabelle aus VDI 2081 Blatt 1/7.3.2” beside the coefficients $a_1$, $a_2$, $b_1$ and $b_2$.
• The print: the coefficients $0,255$, $0,015$, $-2,82$ and $-2,91$ are credited to Section 7.3.2 of Blatt 1.
• The problem: Section 7.3 of VDI 2081 Blatt 1:2001-07 is “Luftschalldämmung eines Bauteils”, the airborne sound insulation of a building component, and has no such table. The coefficients are printed in Section 7.2.3.2, “Kulissenschalldämpfer”, on printed folio 52, whose table gives exactly those four values in its 200 mm row, which is the splitter thickness the element uses.
• Consequence: a reader following the reference lands in the wrong chapter. The values themselves are right.
• Evidence: the cited clause and the actual one, both read from the printed pages. Verified on PDF page 12 (printed p. 12) of VDI 2081 Blatt 2:2005-05 and PDF page 52 (printed p. 52) of VDI 2081 Blatt 1:2001-07.
• Library behaviour: none; the library cites Section 7.2.3.2.
• Status: unreported.

Recorded here to prevent future “fixes” that would break agreement with the published sources:

• ISO 12354-1:2017 Table L.8 / ISO 12354-2:2017 Table G.8, first row: the row labelled “Int. wall 1/2 – Ext. wall 1/2” prints $m_i^{\prime }=219,0{\text{kg/m}}^2$ and $m_{\perp i}^{\prime }$ (Part 2: $m_{\text{orthogonal}}^{\prime }$) $=360,0{\text{kg/m}}^2$, which is the assignment for a path leaving the external wall, the opposite of the direction the row’s own label gives. Read in the row’s direction the element carrying the path is the internal wall, so $m_i^{\prime }$ should be 360,0 and the perpendicular mass 219,0. It is a labelling slip and nothing else: the branch is the rigid-T corner branch $K_{12}=5,7+5,7M^2$, where only $M^2$ enters, so both assignments return the same 5,965 → 6,0 dB. The second row of each table, “Ext. wall 1/2 – Ext. wall 1/2”, is the through branch $5,7+14,1M+5,7M^2$, where the sign of $M$ does matter, and it is labelled and populated consistently ($M={\log }_{10}(360/219)$ gives 9,006 → the printed 9,0). Verified on PDF page 89 (printed p. 83) of ISO 12354-1:2017 and PDF page 46 (printed p. 40) of ISO 12354-2:2017. Not registered as an erratum because no number depends on it; registered here so that a future reader does not “correct” the library’s per-path convention to match the printed row.

• Francois-Garrison pure-water term: the two published $A_3$ cubics do not meet exactly at the 20 °C switch (a step of $1\cdot 10^{-7}{f}^2\text{dB/km}$, 0.1 dB/km at 1 MHz). Inherent in the published coefficients.

• Ainslie-McColm simplification: the paper’s “within 10 % of Francois-Garrison” claim is marginally exceeded at the extreme corners of its stated domain (10.4 % at −6 °C / 1 MHz; 12.3 % at 7 km depth). A property of the published fit; both transcriptions verified digit-for-digit.

• CNOSSOS-EU Annex II 2.3, missing equation number: the railway section numbers its formulae (2.3.1), (2.3.2), (2.3.4), (2.3.5)…, with no (2.3.3) anywhere in Annex II. Verified on PDF page 17 (printed p. L 168/17) of Directive (EU) 2015/996:2015, where (2.3.2) and (2.3.4) sit one above the other. Nothing is missing from the method; only the numbering skips.

• CNOSSOS-EU corrigendum of 2018, Table G-3 column codes: the corrigendum is reported to head the seven $L_{r,TR}$ columns “B/S B/M B/H B/S B/M B/H B/H”, where the first three should read “M/S M/M M/H” and the last “W”, and Commission Delegated Directive (EU) 2021/1226 Annex point (20)(c) does replace that header with the corrected codes plus a new column D. It is left unregistered because the corrigendum itself is published only as HTML on EUR-Lex, so no printed page of it could be obtained here, and this registry does not record a claim about a printed symbol that has not been read off the page. The 2015 print of the same table, which was read, carries descriptive headers (“Mono-block sleeper on soft rail pad” and so on) and no defect.

• Long, Architectural Acoustics 2e, Chapter 17, adjacent-table level: the restaurant example states that “at an adjacent table 3 m (10 ft) away, the direct field level from our conversation is about 54 dB”, where his own Eq. (17.50) with the $Q=2$ and $L_W=70\text{dB}$ that yield his 60 dB at 1.2 m gives 52.5 dB. It is left unregistered because the intended reading cannot be established from the book: 54 dB is also what the same equation gives at 2.5 m (54.1 dB, and 2.5 m is the table spacing the next paragraph derives), and what a single 6 dB distance doubling from the rounded 60 dB would give, while the printed “3 m (10 ft)” is self-consistent in both units and is repeated in the preceding paragraph. speech_direct_level evaluates Eq. (17.50) as printed, so it returns 52.5 dB there; do not “correct” it toward 54 dB.

• ICAO Annex 16 EPNL constant: the Annex’s rounded constant 13 for uniform 0.5 s records differs from the exact $-10{\log }_{10}(T_0)$ form by 0.0103 dB; the library uses the exact form, which the ETM’s integrated reference reproduces to five decimals.

• Long Table 14.9 element rows: the worked duct-borne sheet of Chapter 14 was produced by a commercial program, as the text introducing it states, and several of its element rows do not follow from the tables printed beside them: the fan row (90/86/82/79/77/75/71/61 dB) is not what Eq. 13.1 gives with the Table 13.5 forward-curved constants at that duty (99/99/89/84/82/77/72/67 dB, and not a level shift of it), and the flexible-duct row (14/14/16/15/17/22/16/13 dB) is not the Table 14.4 entry for 12 in by 6 ft (3/5/10/15/17/16/9 dB). The library implements the printed equations and tables, and uses the sheet only for what it genuinely pins, the cascade arithmetic; its element rows are fed in as published in tests/noise_control/test_duct_path.py. The sheet’s own rounding is likewise not always self-consistent (supply row 3 prints a Sum of 49 dB at 500 Hz where $76-28=48$, then a Combined consistent with 48), which is why the comparison runs at the 1 dB the printed sheet carries.

• ISO 3747:2010 Table E.1, the accuracy-grade labels: the informative table of worked ${\sigma }_{\mathrm{tot}}$ examples labels its three rows “0,5 (accuracy grade 1)”, “1,5 (accuracy grade 2)” and “3 (accuracy grade 3)”, while the normative Table 2 of this part gives ${\sigma }_{R0}$ = 4,0 dB for survey grade 3 and the scope of ISO 3747 covers grades 2 and 3 only. It is the ISO 3740 family’s shared illustration, not a statement about this method: ISO 3744:2010 Table H.1 prints the identical table, rows, labels and ${\sigma }_{\mathrm{tot}}$ cells alike, and ISO 3744 covers grade 2 only. Verified on PDF page 42 (printed p. 33) and PDF page 27 (printed p. 18) of BS EN ISO 3747:2010. The library reads ${\sigma }_{R0}$ from the normative Table 2 (1,5 dB and 4,0 dB, conformance check “ISO 3747:2010 Table 2 / Eq. 22”) and uses Table E.1 only for its ${\sigma }_{\mathrm{tot}}$ = 1,6 / 2,5 / 4,3 row against ${\sigma }_{R0}$ = 1,5 dB, where the two tables agree. Do not “correct” the 3 dB row to 4,0 dB: it belongs to the family’s illustration, not to this part’s Table 2.

• ISO 3747:2010 Annex C, ${\theta }_{\mathrm{ref}}$ = 296 K: the annex prints the reference temperature of the radiation-impedance correction as 296 K beside a reference condition of 23,0 °C, which is 296,15 K, so at exactly the reference conditions $C_2=15\lg (296,15/296)=+0,0033$ dB rather than zero. ISO 3741:2010 clause 9.1.4 and ISO 3744:2010 print the same ${\theta }_1$ = 296 K, so it is the family’s rounding and not a misprint of one part; the library keeps 296 K in the shared C2 of sound_power_reverberation.py and pins the residual (conformance check “ISO 3747:2010 Annex C”). Do not “correct” it to 296,15 K.

• ISO 3747:2010 Eq. (14), the single-event background margin: $\Delta L_{Ei}=L_{Ei,q(\mathrm{ST})}^{\prime }-L_{pi(\mathrm{B})}$ subtracts a time-averaged background level from a time-integrated single event level, asking only that both be measured over the same integration time $T$. The difference is a true margin for $T$ = 1 s; for a longer $T$ the background holds $10\lg (T/T_0)$ dB more energy over the event’s interval (clause 3.4, NOTE 1). ISO 3741:2010 Eq. (25) and ISO 3744:2010 clause 8.3.4 print the same line, verified on PDF page 23 (printed p. 14) of BS EN ISO 3747:2010 and on the corresponding pages of the two siblings, so it is the family’s convention and is not registered against one part. The library applies Eq. (14) as printed by default and offers integration_time on sound_energy_in_situ to carry the background to the event’s interval first.

• ISO 5136:2003, clause 5.3.4.3, the sign of Equation (8): the clause says the corrections of the nose cone and the foam ball “are estimated to be negative and of small magnitude”, and then prints $C_{3,4}=10\lg [1/(1-U/c{)}^2]$ dB, which is positive whenever $U>0$: at the 20 m/s the nose cone is allowed, with $c$ = 340 m/s, $+0,53$ dB on the outlet side and $-0,50$ dB on the inlet side. The equation’s sign is the one the convected plane wave gives, the energy flux of a wave travelling with the flow being $(1+M{)}^2$ times $p^2/\rho c$, so for a given pressure the power is higher downstream and lower upstream. It is not registered as an erratum because the closing sentence of the same paragraph reconciles the two: “With this simplification, the sound power level obtained by using the nose cone or foam ball is expected to be higher than the true sound power level.” The negative correction is the modal one, which is unavailable and is dropped; Equation (8) is the convective part that is kept, and the standard says in the same breath that what is left biases $L_W$ high. Read on PDF page 29 (printed p. 19) of ISO 5136:2003. Registered here so that nobody “corrects” the sign of Equation (8), which flow_modal_correction implements as printed and test_eq8_omnidirectional_shields in tests/emission/test_sound_power_in_duct.py pins.