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phonometry

Hearing and perception

By José M. Requena Plens · Published , updated

A sound pressure level says how much sound there is; this section is about what a listener makes of it. Its three subsections answer three different questions. Psychoacoustics quantifies sensations: how loud a sound is perceived to be, how sharp, rough or tonal it is, and how those sensations combine into annoyance. Speech asks how well spoken words survive the trip from a talker to a listener, through a room, a sound system or background noise. And hearing and exposure covers the ear itself: where the hearing threshold sits across age and population, how noise permanently shifts it, and how a working day’s exposure is measured and reported.

The three build on each other in one direction: the psychoacoustic models consume calibrated signals or band spectra from the core analysis; the speech indices consume band levels and, in the SII’s case, the hearing thresholds that the exposure pages quantify; and the exposure metrics feed the hearing-damage model of ISO 1999.

A good entry point is Loudness: it introduces the perceptual scale (the sone) and the auditory models that most other metrics in this section reuse or extend.

Psychoacoustics

Section titled “Psychoacoustics”

The perceptual sensations of sound: loudness and the metrics layered on it.

Speech

Section titled “Speech”

Two complementary indices of speech intelligibility: STI rates the transmission channel, SII rates the listening condition.

Hearing and exposure

Section titled “Hearing and exposure”

The hearing threshold, what noise does to it, and how exposure is measured.

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