@maruaudio/dsp/dynamics/keyed-compressor is a feed-forward, log-domain compressor with a sidechain key: optional detector filters, peak or RMS level in dB, a quadratic soft-knee gain computer (Giannoulis, Massberg and Reiss, JAES 2012), one-pole smoothing of the reduction with an integer hold, a range ceiling and a dry/wet mix. Ratio 1000 is the limiter sentinel. It also exports the auto-makeup, stereo link and crest-factor auto-release laws.

const state = initDynamicsCompressorNode(48000)
updateDynamicsCompressorBlock(state) // once per block
const y = dynamicsCompressorNodeTick(state, x, key) // key = x for internal

Parameters

Setters are setDynamicsCompressor<Name>(state, value).

Lifecycle

initDynamicsCompressorNode(sampleRate) → setters → updateDynamicsCompressorBlock once per block (makeup and release coefficient, from the crest state with auto-release) → dynamicsCompressorNodeTick(state, input, key) → resetDynamicsCompressorNode, which clears history and keeps the settings. prepareDynamicsCompressorNodeSampleRate re-derives rate values.

When to use it

Bus or channel compression, or ducking one signal under a key such as a kick.

Limits

• Mono with one key input; a zero key gives no reduction, so an unpatched sidechain is bypass. Stereo linking is the caller's.
• Math.exp runs only at block rate; per sample, log, pow and, in RMS mode, sqrt. Reduction, RMS and crest states are f32; detector filters at their defaults are skipped.