@audio/weighting-riaa

RIAA playback equalization — vinyl de-emphasis curve

npm install @audio/weighting-riaa

import riaa from '@audio/weighting-riaa'

Time-domain RIAA de-emphasis: bilinear transform (with frequency prewarping) of the analog playback curve H(s) = (1 + s·T2) / ((1 + s·T1)(1 + s·T3)), T1=3180 µs (fp1≈50.05 Hz pole), T2=318 µs (fz≈500.5 Hz zero), T3=75 µs (fp2≈2122 Hz pole) — the standard RIAA time constants, folded into a single biquad. 1 second-order section, normalized to exactly 0 dB at 1 kHz.

riaa(data)                                // in place, fs=44100
riaa(data, { fs: 48000 })
let sos = riaa.coefs(48000)               // 1 SOS section — feed digital-filter's freqz
riaa.response(20, 48000)                  // |H(20)| — the bass-boost region

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

| Static | Returns | | |---|---|---| | .coefs(fs) | SOS | 1-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: decoding a phono-preamp signal that was cut with RIAA pre-emphasis (i.e. reversing vinyl mastering's treble boost / bass cut) back to a flat response.

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

MIT © audiojs