@audio/dynamics-expander

Downward expander: reduces gain below threshold by (T-L)·(ratio-1) dB,

npm install @audio/dynamics-expander

import expander from '@audio/dynamics-expander'

Downward expander (mode: 'downward', default) — a softer gate. Below threshold, gain is reduced by (threshold − level) × (ratio − 1) dB, clamped at range.

mode: 'upward' switches to upward expansion — the de-compression complement, raising gain above threshold instead of cutting it below. Classical substrate for de-limiting: transient-aware upward expansion restores crest factor a brickwall limiter (or an over-eager mix bus compressor) flattened. Same four-quadrant taxonomy as compressor's upward mode (Giannoulis/Reiss; Izhaki, Mixing Audio).

import { expander } from '@audio/dynamics'

expander(data, { threshold: -30, ratio: 2 })

// de-limiting: expand transients back out above threshold
expander(data, { mode: 'upward', threshold: -20, ratio: 1.5, range: 20 })

| Param | Default | | |---|---|---| | mode | 'downward' | 'downward' | 'upward' | | threshold | -30 | dB | | ratio | 2 | — | | knee | 6 | dB | | range | -40 (downward) / 20 (upward) | dB, max reduction (downward, negative) or max lift (upward, positive) | | attack | 5 | ms | | release | 50 | ms |

Use when: gentle noise-floor suppression without the abruptness of a gate (downward); restoring dynamics to over-compressed or over-limited material (upward). Not for: hard removal of sound between phrases — use gate.

Part of @audio/dynamics — the dynamics family umbrella. This README is generated from the umbrella docs.

MIT © audiojs