@audio/measure-align

Multi-mic phase/time alignment — signed cross-correlation delay + polarity (Auto-Align class)

npm install @audio/measure-align

import align from '@audio/measure-align'

Signed cross-correlation peak between two channels gives the delay and polarity of b relative to a; pass apply: true to also get b shifted into alignment and polarity-corrected.

align(a, b, { fs })                       // { delay, seconds, polarity }
align(a, b, { fs, apply: true })           // + { aligned }

| Param | Default | | |---|---|---| | a | — | reference channel (Float32Array) | | b | — | channel to align (Float32Array) | | fs | 44100 | sample rate | | apply | false | when true, also return aligned: b shifted by delay and polarity-flipped |

Returns:

| Field | | | |---|---|---| | delay | number | samples b lags a (signed) | | seconds | number | delay / fs | | polarity | 1 \| -1 | polarity of b relative to a | | aligned? | Float32Array | present only when apply: true |

Use when: multi-mic recordings (drum overheads, DI + amp blend, room + close mics) need per-channel delay and polarity correction before summing — comb-filtering from misaligned mics is inaudible per-track and destructive on sum.

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

MIT © audiojs