@audio/weighting-c

IEC 61672-1:2013 C-weighting filter — near-flat curve for high-SPL measurement

import cWeighting from '@audio/weighting-c'

Time-domain C-weighting: matched-z discretization of the IEC 61672-1:2013 analog prototype H(s) = K·s² / ((s+w1)²(s+w4)²), sharing A-weighting's outer poles — f1=20.598997 Hz (double), f4=12194.217 Hz (double) — but no mid-band poles, giving a near-flat response across the audible range. 2 second-order sections, normalized to exactly 0 dB at 1 kHz.

cWeighting(data)                          // in place, fs=44100
cWeighting(data, { fs: 48000 })
let sos = cWeighting.coefs(48000)         // 2 SOS sections — feed digital-filter's freqz
cWeighting.response(1000, 48000)          // |H(1000)| — 1.0 (0dB normalization)

Use when: measuring high-SPL or low-frequency-heavy sources (peak/impulse SPL, subwoofer output) where A-weighting's low-end rolloff would understate levels.

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

MIT © audiojs