Brown Noise Generator

Brown noise is a deep, steady rumble, like a waterfall or strong wind, with much more bass than white or pink noise. Many people use it to mask distracting sounds while they sleep, read or work. This generator makes a fresh file of up to an hour, in stereo with a different noise in each ear, with soft fades or as a seamless loop, all inside your browser.

How to use this tool

1. Choose the length and the format: MP3 for long files, WAV for a perfect loop.
2. Pick the tone (Deeper removes more of the hiss) and the level.
3. Press Calculate; long MP3 files take a little while to make.
4. Play it here or download it, and turn on loop in your player for endless noise.

Formula

bₙ = (bₙ₋₁ + 0.02 × wₙ) ÷ 1.02 · output = 3.5 × b × gain

w is white noise. The leaky integrator turns it into noise whose power falls by 6 dB per octave (1/f²) above about 140 Hz at 44.1 kHz, and stays flat below so the signal cannot drift. The gain is set from a 20-second calibration run so the average (RMS) level matches your choice. A seamless loop crossfades the last 3 s with the noise that came just before the start, using equal-power curves. MP3 files are made by the ffmpeg engine (about 30 MB, downloaded once), whose noise source uses this same formula.

Example

A 60-minute stereo MP3 at 160 kbps takes 160,000 ÷ 8 × 3,600 = 72,000,000 bytes ≈ 69 MB. A 10-minute seamless WAV loop is 44,100 × 2 × 2 × 600 ≈ 106 MB, so for long sessions MP3 is the practical choice.