@audio/weighting-d

IEC 537 D-weighting filter — aircraft-noise curve with a resonant hump near 3.3 kHz

npm install @audio/weighting-d

import dWeighting from '@audio/weighting-d'

Time-domain D-weighting: matched-z discretization of the IEC 537 analog prototype H(s) = s(s²+6532s+4.0975e7) / [(s+1776.3)(s+7288.5)(s²+21514s+3.8836e8)] — one zero at DC plus a complex zero pair, two real poles plus a complex pole pair. The only weighting curve with a resonant peak rather than a monotonic rolloff: ≈+11.6 dB near 3.3 kHz (+11.5 dB at the IEC 537 3.15 kHz third-octave reference point), matching the ear's sensitivity to aircraft flyover noise. Withdrawn from the modern standard. 2 second-order sections, normalized to exactly 0 dB at 1 kHz.

dWeighting(data)                          // in place, fs=44100
dWeighting(data, { fs: 48000 })
let sos = dWeighting.coefs(48000)         // 2 SOS sections — feed digital-filter's freqz
dWeighting.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 | 2-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 of aircraft/jet-engine noise; the only weighting curve tuned for that resonant 3–4 kHz band rather than general SPL.

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

MIT © audiojs