Brown noise generator
Deep, rumbly noise made live in your browser. Free, no ads, no account. Press play, set a timer, done.
Keep it soft. If you’d have to raise your voice to talk over it, turn it down.
In the Lab it runs as an 8-hour sleep session with sand visuals. Brown noise is part of Pro (7-day free trial; rain is free).
What brown noise is
MeasuredBrown noise is random sound with most of its energy in the low end. Its power per hertz falls by 6 dB (to a quarter) every octave. Each octave is twice as wide as the one below, so each octave up still carries half the energy of the one below. That’s why it sounds like a low rumble, heavy surf or a car on the highway rather than a hiss.
It’s named after the botanist Robert Brown, not the colour. The signal wanders like a particle in Brownian motion, a random walk. You’ll also see it called red noise.
Brown vs pink vs white noise
| White | Pink | Brown | |
|---|---|---|---|
| Spectrum (per hertz) | Flat | Falls 3 dB per octave | Falls 6 dB per octave |
| Energy per octave | Doubles each octave up | The same in every octave | Halves each octave up |
| Sounds like | Hiss, TV static | Steady rain, rustling leaves | Low rumble, distant surf |
Use the Brown, Pink and White buttons on the player to hear the difference. Most people find brown the least harsh.
Brown noise for sleep
StudiesA steady sound covers sudden ones, like a door, traffic or a partner’s snoring, and that’s the main reason people sleep with noise on. Whether it improves sleep is less settled: a 2021 systematic review rated the evidence that continuous noise helps sleep as very low quality[1]. Brown noise in particular has barely been studied; most studies used white or pink noise.
If you use it, keep it quiet and use the timer, or let it run all night at a low level. For babies, keep any sound machine well away from the cot and turned down: a 2014 study measured infant sleep machines and found some could exceed recommended noise limits at full volume[2].
Brown noise for focus and ADHD
StudiesPeople use brown noise to drown out chatter while they work. One line of research found that moderate white noise helped children with ADHD on memory tasks, while it made children without ADHD perform worse[3]. Those studies used white noise, and nobody has shown brown noise treats ADHD. If it helps you get work done, that’s reason enough to use it.
How this player makes it
MeasuredThe sound is made on your device from random numbers, run through a leaky running sum (the standard recipe for brown noise; pink uses Paul Kellet’s filter). It plays 20 seconds of noise that loops without a seam, with the left and right ears independent. Nothing is downloaded or uploaded.
Sleeping with it? Try Wind-Down
Seven nights of sleep sounds, from soft pads and rain to a slow delta beat and brown noise. Night 1 is free.
Questions
Is brown noise better than white noise for sleep?
No study shows one colour is best for everyone. Many people find brown noise less harsh because it has less hiss. Try each one on the player for a minute and keep the one you’d forget is on.
Is it safe to play brown noise all night?
Hearing risk comes from loudness and time together, and the World Health Organization’s safe-listening guidance sets limits on both[4]. For something that plays all night, a sensible rule of thumb is quieter than normal conversation.
Why is it called brown noise?
After Robert Brown, who observed the jittery motion of tiny particles from pollen in water in 1827. Brown noise wanders the same way those particles do: a little at a time, in random directions.
Does it work offline?
Once the page has loaded, the sound is made on your device, so it keeps playing without a connection. The full Lab can be installed and works fully offline.
Sources
- Riedy SM, Smith MG, Rocha S, Basner M. Noise as a sleep aid: a systematic review. Sleep Medicine Reviews 55:101385 (2021). doi:10.1016/j.smrv.2020.101385
- Hugh SC, Wolter NE, Propst EJ, Gordon KA, Cushing SL, Papsin BC. Infant sleep machines and hazardous sound pressure levels. Pediatrics 133(4):677–681 (2014). doi:10.1542/peds.2013-3617
- Söderlund G, Sikström S, Smart A. Listen to the noise: noise is beneficial for cognitive performance in ADHD. Journal of Child Psychology and Psychiatry 48(8):840–847 (2007). doi:10.1111/j.1469-7610.2007.01749.x
- World Health Organization. Make Listening Safe. who.int/activities/making-listening-safe