Question 1

How does the audio noise reducer work?

Accepted Answer

Drop or pick an audio file. We decode it with the Web Audio API, split it into small overlapping windows (e.g. 1024 samples), apply a Hanning window, and run an FFT on each. The first ~100ms of the signal is treated as a noise sample: we average its magnitude spectrum to estimate the noise floor. For every subsequent window we subtract a scaled copy of the noise floor from the magnitude (clamped at zero), keep the original phase, and run an inverse FFT. We then overlap-add the windows back together. An optional noise gate silences samples below a dBFS threshold. The result is re-encoded as a 16-bit PCM WAV file (pure-JS RIFF encoder, no library).

Question 2

What strength and noise-gate presets are available?

Accepted Answer

Four strength presets control how aggressively the noise floor is subtracted: light (25), medium (50), strong (75), and aggressive (100). Higher values remove more noise but may introduce musical-noise artifacts. Four noise-gate threshold presets are also available: -30 dBFS (gentle), -40 dBFS (default), -50 dBFS (aggressive), and -60 dBFS (only the quietest hiss). Anything quieter than the threshold is silenced.

Question 3

What FFT sizes can I choose?

Accepted Answer

Five power-of-two FFT sizes: 256, 512, 1024 (default), 2048, and 4096. Smaller sizes track transient noise better; larger sizes give finer frequency resolution but smear attacks. A 50% hop size and Hanning window with overlap-add reconstruction guarantee perfect reconstruction when no subtraction is applied.

Question 4

What extra features does this tool have compared to others?

Accepted Answer

(1) 4 strength presets (light/medium/strong/aggressive). (2) 4 noise-gate threshold presets (dBFS). (3) 5 FFT sizes. (4) Noise estimation from a sample window (average magnitude spectrum). (5) Spectral subtraction algorithm (subtract scaled noise floor, clamp to zero). (6) Noise-gate applier (silence samples below threshold). (7) Hanning window generator. (8) Magnitude/phase calculator from complex FFT. (9) Reconstruction from magnitude/phase via inverse FFT. (10) Pure-JS radix-2 Cooley-Tukey FFT + IFFT. (11) File-size estimator. (12) WAV encoder (44-byte RIFF header + 16-bit PCM). (13) Text report generator. (14) CSV report generator. (15) History (localStorage, last 20). (16) Shareable URL settings. (17) Summary stats (input level, noise level, output level, % noise reduced, clipping prevented).

Question 5

Is my data sent anywhere?

Accepted Answer

No. The audio file you load, decoded samples, FFT data, and output WAV never leave your browser. There is no upload. Noise-reduction metadata in history is stored in localStorage on this device only.

Audio Noise Reducer

Denoise settings

How to use

Denoise settings