@audio/ir
Status calibrated
npm1.0.2licenseMIT
Impulse-response capture — exponential sine sweep deconvolution (Farina 2000), self-calibrated
import ir from '@audio/measure-ir'
Farina exponential-sine-sweep (ESS) deconvolution: the inverse filter is the time-reversed sweep with exp(−t/L) amplitude compensation for the sweep's 1/f energy density. Convolving the recording with it collapses the sweep to an impulse at t=0; harmonic distortion products land at negative time and are trimmed away — the ESS advantage over linear sweeps or MLS. Self-deconvolution of the sweep against its own inverse filter calibrates the output so an identity system (recorded === sweep) yields δ = 1.0.
Farina, A. — Simultaneous Measurement of Impulse Response and Distortion with a Swept-Sine Technique, AES 108th Convention, 2000.
let h = ir(recorded, { sweep, f0: 20, f1: 20000, fs, length: 1000 })
| Param | Default | |
|---|---|---|
sweep |
— | required — the exponential sine sweep that was played (Float32Array) |
f0 |
20 |
sweep start frequency, Hz |
f1 |
fs/2 * 0.95 |
sweep end frequency, Hz |
fs |
44100 |
sample rate |
length |
recorded.length - sweep.length + 1 |
samples of IR to return |
Returns a Float32Array: the impulse response, direct path at index 0, calibrated to unit gain. Throws RangeError if opts.sweep is omitted.
Also exports convFFT(a, b) (zero-padded FFT convolution) and inverseSweep(sweep, {f0, f1, fs}) — the building blocks @audio/measure-align and @audio/measure-latency reuse for their own cross-correlation.
Use when: capturing the impulse response of a room, cabinet, or signal chain from a recorded exponential sweep — feeds @audio/reverb-convolution and @audio/amp-cabinet.
Part of @audio/measure — the measure family umbrella.
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