@audio/weighting-a

IEC 61672-1:2013 A-weighting filter — the standard SPL-meter curve

npm install @audio/weighting-a

import aWeighting from '@audio/weighting-a'

Time-domain A-weighting: matched-z discretization of the IEC 61672-1:2013 analog prototype H(s) = K·s⁴ / ((s+w1)²(s+w2)(s+w3)(s+w4)²) with poles at f1=20.598997 Hz (double), f2=107.65265 Hz, f3=737.86223 Hz, f4=12194.217 Hz (double) — 3 second-order sections, normalized to exactly 0 dB at 1 kHz.

aWeighting(data)                          // in place, fs=44100
aWeighting(data, { fs: 48000 })
let sos = aWeighting.coefs(48000)         // 3 SOS sections — feed digital-filter's freqz
aWeighting.response(1000, 48000)          // |H(1000)| — 1.0 (0dB normalization)

| Param | Default | | |---|---|---| | fs | 44100 | sample rate — SOS recomputed when it changes mid-stream |

| Static | Returns | | |---|---|---| | .coefs(fs) | SOS | 3-section cascade at rate fs, for analysis/plotting | | .response(f, fs) | number | \|H(f)\| — exact magnitude of this atom's own .coefs(fs) cascade, not an independent approximation |

Use when: measuring or matching perceived loudness at low-to-moderate SPL — the standard curve for consumer/broadcast loudness meters and most "dBA" specs.

Part of @audio/weighting — the weighting family umbrella.

MIT © audiojs