This brown noise generator plays deep brown noise made in your browser, with an exact 1/f² spectrum: its energy per hertz falls 6 dB every time the frequency doubles, so the sound is all rumble and almost no hiss. It is the noise people describe as a waterfall, a jet cabin or heavy rain on a roof. Use it to cover low background sounds, to sleep or to focus, with a sleep timer that fades it out slowly, in stereo or mono. It works on phones, tablets and computers, and sounds best through headphones or a speaker with real bass.
How to play brown noise
- Turn your device volume down, then press Play brown noise.
- Raise the volume until the noise covers the sound you want to hide. Brown noise is deceptive: its bass can be louder than it feels.
- Pick Stereo for a wide sound or Mono for a centred one.
- Set a Sleep timer and Fade out for bedtime. A 5 minute fade is barely noticeable.
- On a phone, turn on Keep playing with the screen off before pressing Play.
- Press Download a loop as WAV if you want the noise in your own music player.
What brown noise is
Brown noise is what you get when you add up random steps: each new sample is the last one plus a small random change, like a particle drifting in Brownian motion. That builds slow, rolling swings into the sound, which is why it rumbles. In numbers, its power per hertz is proportional to one over the frequency squared. Each octave up carries a quarter of the power per hertz, a drop of 6 dB, so on the third octave bars the level falls steadily to the right, about 3 dB per octave. Very slow swings below 12 Hz are filtered out here, because nobody can hear them and they only make speaker cones move.
What the readouts mean
| Readout | What it tells you | Normal value |
|---|---|---|
| Color | The noise playing and its spectrum | Brown noise, 1/f² spectrum |
| Slope | Change in power per hertz for each octave | −6 dB |
| Level | RMS level sent to your system before its volume | −28 dBFS at 50% volume |
| Timer | Time left on the sleep timer | Counting down, or off |
| Channels | Stereo or mono | Stereo |
Brown, pink and white noise compared
| Feature | Brown | Pink | White |
|---|---|---|---|
| Energy per hertz, each octave up | −6 dB | −3 dB | Same |
| Bars on the display | Fall to the right | Level | Rise to the right |
| Sounds like | Low roar, surf, a plane cabin | Steady rain | Hiss, a fan |
| Hides best | Traffic, engines, bass from next door | Voices and general noise | Voices and high pitched noise |
Switch between the three with the Color keys while the noise plays; it crossfades, so you can compare them at the same level. The pink noise page explains its use for speaker calibration, and the white noise generator page covers the research on noise and sleep in more detail.
Brown noise for focus, ADHD and sleep
Brown noise became popular through social media, with many people with ADHD saying it quiets their thoughts. That experience is real for them, but research on brown noise itself is close to nonexistent: a 2024 review by Nigg and colleagues looked for studies of brown noise and ADHD and found none (Journal of the American Academy of Child and Adolescent Psychiatry). The studies of noise and attention it did find used white or pink noise, which helped young people with ADHD or strong ADHD symptoms a little on tasks and made those without ADHD do a little worse. For sleep, a 2021 systematic review by Riedy and colleagues in Sleep Medicine Reviews judged the evidence that continuous noise improves sleep to be of very low quality.
So treat brown noise as a comfort tool, not a treatment. If it helps you, use it at a low level. If you find it distracting or it makes you drowsy when you need to work, it is not for you.
Brown noise sounds thin, hissy or quiet
- Phone or laptop speakers. Most of brown noise sits below 200 Hz, where small speakers produce almost nothing. You hear only the faint upper part. Use headphones, a Bluetooth speaker with real bass, or switch to pink noise.
- Bass reduced by a setting. An equalizer, a "voice" sound mode or a bass cut on the speaker removes the heart of it. Turn those off.
- Cheap earbuds with a poor seal. Bass leaks out when earbuds do not seal. Try a larger ear tip size; the headphone test can confirm the bass.
It rumbles, buzzes or distorts
Brown noise asks a lot of a speaker, because deep sound moves the cone furthest. If it rattles or buzzes, turn the volume down first. If a speaker buzzes even at a low level, check for loose objects on or near it, then try another speaker to see whether the fault follows the speaker. With Bluetooth speakers, a strong bass boost mode can make brown noise pump; turn it off.
What this brown noise player cannot measure
The tool sets the digital level and spectrum exactly, but not how loud the noise is at your ears. Deep sound is easy to underestimate, so check the level at your pillow or desk with a decibel meter. The noise is made as a loop of about 22 to 24 seconds that repeats without a click, with the same spectrum as endless noise. It is not a medical treatment for ADHD, anxiety, insomnia or tinnitus.
Brown noise questions
What is brown noise good for?
Mostly for covering low, rumbling sounds such as traffic, an air conditioner or a neighbour's music, and for people who find white noise too hissy. Many use it to sleep, study or calm a busy mind. Those uses rest on personal experience rather than strong research.
Is brown noise good for ADHD?
Some people with ADHD say it helps them focus, but a 2024 review of noise and ADHD research found no studies of brown noise at all. The 13 studies it did find used white or pink noise, which gave young people with ADHD or strong ADHD symptoms a small lift on tasks and made those without ADHD do slightly worse. Try it for yourself and stop if it distracts you.
Brown noise or pink noise, which is better for sleep?
Neither has been shown to be better. Brown noise is deeper and hides low sounds well; pink noise is brighter and hides voices better. Play each for a few minutes at the same low level and keep the one you can ignore.
Why is it called brown noise?
It is named after Robert Brown, the botanist who described Brownian motion, the random jiggling of tiny particles. Adding up random steps, as in that motion, produces this kind of noise. It has nothing to do with the colour brown, and it is also called red noise.
Can I play brown noise all night?
Yes, if you keep it quiet. Deep sound can be louder than it seems, so check the level and keep the speaker away from your head. A sleep timer with a long fade is a good middle ground.
Why does brown noise sound so quiet on my phone?
Most of its energy is below 200 Hz, and phone speakers play almost nothing down there. What you hear is the thin top of the sound. Use headphones or a larger speaker, or switch to pink noise, which keeps more energy in the range a phone can play.