Repairing Diffuse Reverb

masteringRepairDereverbClassical is for a sustained, diffuse tail that masks the direct sound. It uses STFT-domain spectral subtraction and can run an optional WPE pre-stage. It is an offline restoration pass, not room-impulse-response deconvolution and not a way to recover a perfectly dry source.

Detect before dereverb

The detector reports the statistic used by the dereverberator. It does not calculate an ISO 3382 RT60. Use estimateRoom when you need an equivalent-room estimate and inspect its confidence before using it to configure the repair.

import {
  estimateRoom,
  init,
  masteringRepairDereverbClassical,
  masteringRepairDereverbConfigForRoom,
  masteringRepairDetectReverb,
} from '@libraz/libsonare';

await init();

const detection = masteringRepairDetectReverb({
  samples,
  sampleRate,
});
const estimate = estimateRoom(samples, sampleRate, { nOctaveBands: 6 });
console.log(detection.lateDecayRatioDb, detection.latePredictability);
console.log(estimate.confidence, estimate.rt60Bands, estimate.volume);

const config = masteringRepairDereverbConfigForRoom(estimate, {
  attenuation: 0.7,
});
const cleaned = masteringRepairDereverbClassical({
  samples,
  sampleRate,
  ...config,
});

The configForRoom call reads the room estimate and returns a complete dereverb configuration. A real workflow still needs an audition: a low-confidence room estimate or a tail that is actually musical may not justify the pass.

What the room config changes

masteringRepairDereverbConfigForRoom reads only volume and rt60Bands from the estimateRoom result. It changes two timing parameters and leaves the amount of removal under your control.

Option	How to use it
t60Sec	Derived from the mid-band RT60 estimate. If the relevant bands did not converge, the helper uses the documented fallback from the available bands.
lateDelayMs	Derived from the estimated volume as a mixing-time delay, which marks the late diffuse region.
attenuation, threshold, overSubtraction, spectralFloor	Keep or override these amount and gate controls; they are not replaced by room geometry. threshold and attenuation are validated in the [0, 1] range.
nFft, hopLength	Set the STFT geometry.
wpeEnabled, wpeIterations, wpeTaps, wpeStrength	Enable and shape the optional WPE pre-stage. WPE analysis is otherwise off by default.

The Room Acoustics page explains equivalent-room estimates, RT60 bands, and confidence. Its roomMorph effect adds a target-room character; it is a different operation from dereverberation.

Keep channels linked

Use the stereo or linked entry point for multichannel material so one mask controls the set. The common mask preserves interchannel level and phase relationships.

import {
  masteringRepairDereverbClassicalLinked,
  masteringRepairDereverbClassicalStereo,
} from '@libraz/libsonare';

const stereo = masteringRepairDereverbClassicalStereo({
  left,
  right,
  sampleRate,
  attenuation: 0.7,
});

const linked = masteringRepairDereverbClassicalLinked({
  channels: [frontLeft, frontRight, centre],
  sampleRate,
  attenuation: 0.7,
});
console.log(stereo.report.meanReductionDb, linked.report.suppressedFraction);

The dereverb detector and repair pad an input shorter than nFft for analysis. All channels in a stereo or linked call must have the same length. The report contains ratios and fractions, so its values do not acquire the channel-count offset of the denoise floor measurement.

Listen to the existing demo

A/B PROCESS · DEREVERBIDLE

Restoration — a worn record, before and after

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The piano clip contains hum, hiss, clicks and crackle. This example applies only the classical dereverberator, which attenuates diffuse sustained energy; it does not apply a dedicated declick or dehum stage. Compare the spectra and audition the result without added loudness matching. The processor can change musical tails and timbre as well as the noise bed. FLOOR shows the high-band reduction in dB.

Compare

This embedded restoration example applies only the classical dereverberator. It does not run a dedicated declick, dehum, or denoise stage. The pass can change tails and timbre, and the comparison does not add loudness matching.

Limits

The reverb detector is a module-specific late-decay and optional predictability measurement, not a room-acoustic standard. Dereverb attenuates diffuse sustained energy; it does not remove every early reflection, reconstruct a room impulse response, or separate overlapping sources. It can mistake a held note or other sustained musical material for a tail. Keep the untreated signal, compare at the same playback gain, and use the Audio Repair Workflow to place dereverb last after the other supported repairs.

For exact overloads and report fields, see the JavaScript mastering API.