@audio/dynamics-opto

Optical compressor model (LA-2A class) — RMS detection, wide soft knee, program-dependent release

npm install @audio/dynamics-opto

import opto from '@audio/dynamics-opto'

Models a Teletronix LA-2A-style electro-optical gain cell: RMS-detected soft-knee compression (~3:1, wide 10 dB knee) plus the T4 cell's signature — release time that slows the longer gain reduction persists. An internal ~3 s memory of time-under-reduction stretches release up to 7× on sustained material, then relaxes back toward the nominal value once the signal clears.

opto(data, { threshold: -20, ratio: 3 })                 // batch
opto(data)                                                 // defaults

let write = opto({ threshold: -20, ratio: 3 })            // streaming
let out1 = write(block1)
let tail = write()                                         // flush

| Param | Default | | |---|---|---| | threshold | -20 | dB | | ratio | 3 | — | | knee | 10 | dB (wide) | | attack | 10 | ms | | release | 300 | ms (nominal; program-dependent stretch multiplies this up to 7×) | | makeup | 0 | dB | | sampleRate | 44100 | Hz (alias fs) |

Use when: vocals, bass — smooth, program-dependent gain riding without pumping. Not for: fast peak-catching character — use fet. Aggressive drive-dependent ratio — use varimu.

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

MIT © audiojs