Brown Noise Player
What is brown noise?
Brown noise is random sound whose power falls by 6 decibels for every doubling of frequency. That puts most of its energy in the bass, so it sounds like a deep, steady rumble — a distant waterfall or heavy rain on a roof — rather than the bright hiss of white noise. It is also called red noise or Brownian noise.
Where the name comes from
In 1827 the botanist Robert Brown watched pollen particles in water through a microscope and saw them jitter about at random. That motion — Brownian motion — is a random walk: each position is the last one plus a small random step. Turn a random walk into sound and you get brown noise. The “brown” is Robert Brown, not the colour, although by analogy with light it is also called red noise: it is weighted toward the low end of the spectrum, as red is in light.
What the 6 dB per octave means
An octave is a doubling of frequency. In white noise every frequency carries the same power, so each octave up holds twice as much energy as the one below it, which is why white noise sounds hissy. In brown noise the power at each frequency is proportional to 1/f²: it drops by 6 dB, to a quarter, each time the frequency doubles. The sound at 100 Hz is about 40 dB stronger than at 10,000 Hz, so you hear the rumble and very little of the top end.
How it is generated
Mathematically, brown noise is the running total (the integral) of white noise. A pure running total wanders off without limit, so practical generators, including the player on this site, use a leaky integrator that slowly pulls back toward zero, then filter out the subsonic drift below about 20 Hz that a speaker can’t reproduce anyway. Further low-pass filters give the darker variants: the Deep sound in our player, for example, rolls off steeply above 200 Hz.
Because the sound is calculated from random numbers as it plays, there is no recording and nothing loops. Many brown noise videos and apps play a recording of a few minutes or hours on repeat; if you’re sensitive to hearing the seam, a generator avoids it entirely.
Brown noise in the real world
- Surf and waterfalls heard from a distance (the air absorbs the high frequencies)
- Heavy rain on a roof, and strong steady wind
- The cabin of an airliner at cruise
- Fluctuations in many natural systems — in physics and finance, any process that accumulates random changes behaves like a random walk
How it compares to other noise colours
White noise is flat, pink noise falls 3 dB per octave, and brown noise falls 6 dB per octave, so each is darker than the last. The full comparison, with uses for each, is on brown vs white vs pink noise.
Frequently asked questions
Why is it called brown noise?
After Robert Brown, the botanist who described the random jittering of particles in water in 1827 — Brownian motion. Brown noise is the sound of that kind of random walk. The name has nothing to do with the colour brown.
Is brown noise the same as red noise?
Yes. Red noise and Brownian noise are other names for the same thing: a spectrum falling at 6 dB per octave, or power proportional to 1/f².
What does brown noise sound like?
A low, smooth roar: a waterfall heard from a distance, heavy rain on a roof, strong wind, or the inside of an airliner at cruise. It has much less hiss than white noise.
Is brown noise the same as the “brown note”?
No. The “brown note” is an internet myth about a sound frequency that supposedly affects the bowels. Brown noise is a well-defined signal used in acoustics and physics.
How is brown noise made?
By adding up white noise over time — each sample is the previous one plus a small random step. Real generators let the sum leak back toward zero and filter out the very lowest frequencies, so it never drifts out of range.