SleepLog / Sleep sounds / Brown noise
Brown noise player
Brown noise for sleep
A deep, steady rumble, like distant thunder or a big waterfall. Press Play, set a timer, and add rain or the sea if you like.
This brown noise is made live in your browser with the same recipe as the SleepLog iPhone app, so there's no loop point to catch your ear.
Pick a sound or two, then press Play. The timer fades them out over the last 30 seconds.
On a phone, your browser may stop the sound when the screen locks. The SleepLog app keeps playing all night.
Brown noise and a snoring check, in one app
SleepLog plays sleep sounds while it listens for snoring, coughing and sleep talking, then shows you the night in the morning.
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Updated 22 October 2026
What is brown noise?
Brown noise is random sound that gets about 6 dB quieter every time the frequency doubles, so it is mostly bass: a deep rumble rather than a hiss.
It's named after Robert Brown, the botanist who described Brownian motion, not after the color. It works like a random walk: each moment is the last one plus a small random step. That smooths out the high frequencies that make white noise sound sharp. People also call it red noise or Brownian noise.
Is brown noise good for sleep?
It may help you fall asleep by covering low, irregular noise, but the research is thin: a 2021 review of 38 studies rated the evidence that continuous noise improves sleep as very low quality.
Studies of brown noise on its own are rare; most research tests white or pink noise. What brown noise does well is mask low sounds such as traffic, a fridge hum or a TV through the wall, and many people find it less tiring than white noise. If it relaxes you, it's worth a try. Keep the volume low and use the timer if you only need it to fall asleep.
Brown noise vs pink noise vs white noise
All three are random noise; the difference is the balance of low and high sound. Brown is the deepest, white the brightest, and pink sits between them.
| Brown noise | Pink noise | White noise | |
|---|---|---|---|
| Loudness as pitch doubles | Drops about 6 dB | Drops about 3 dB (equal energy in every octave) | Stays the same |
| Sounds like | Distant thunder, a strong waterfall | Steady wind, rain on leaves | An untuned radio, a fan on high |
| Feels | Deep and soft | Balanced | Bright, can feel harsh |
| Best at covering | Traffic, rumble, a TV next door | A mix of everyday noise | Voices, footsteps, sharp sounds |
Try each in the player above: tap Brown noise, then Pink noise, then White noise. Most people settle on the deepest one that still covers the noise that bothers them.
Does brown noise help you focus?
Some people say it helps them concentrate, and it became popular on social media for that, but there is little direct research on brown noise and focus.
If a steady sound helps you shut out a noisy office or home, brown noise is easy to listen to for long stretches because it lacks sharp high tones. Use it at a low volume, and take breaks from headphones. It isn't a treatment for attention problems.
How is this brown noise made?
Your browser adds a small random step to a running total tens of thousands of times a second and gently pulls it back towards zero, which gives brown noise its 6 dB drop each time the frequency doubles.
It's the same recipe the SleepLog iPhone app uses. Because it's generated, not recorded, it never repeats, and nothing is downloaded or sent anywhere.
Questions
What is brown noise?
Brown noise is random sound that gets about 6 dB quieter every time the frequency doubles, so it is mostly low frequencies and sounds like a deep rumble, like distant thunder or a strong waterfall. It is named after Robert Brown and Brownian motion, not the color.
Is brown noise better than white noise for sleep?
Neither is proven better. Brown noise is deeper and many people find it softer, while white noise is better at covering voices and sharp sounds. A 2021 review of 38 studies rated the evidence that continuous noise improves sleep as very low quality, so choose the one you find most relaxing.
Is it safe to sleep with brown noise all night?
Keep it quiet and away from your head. A 2014 study of 14 infant sleep machines found all of them exceeded 50 dBA at 30 cm. If you only need it to fall asleep, a 30 to 60 minute timer is enough.
Sources
- Kasdin NJ. Discrete simulation of colored noise and stochastic processes and 1/fα power law noise generation. Proceedings of the IEEE. 1995;83(5):802–827.
- Riedy SM, Smith MG, Rocha S, Basner M. Noise as a sleep aid: a systematic review. Sleep Medicine Reviews. 2021;55:101385.
- Hugh SC, Wolter NE, Propst EJ, Gordon KA, Cushing SL, Papsin BC. Infant sleep machines and hazardous sound pressure levels. Pediatrics. 2014;133(4):677–681.
- SleepLog iPhone app, sleep sound recipes (SleepSoundPlayer), checked 22 October 2026.
Brown noise tonight. Your night, heard tomorrow.
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