Brown, pink and white noise: what the colours mean
Updated 21 September 2026 · KirsuLab
White, pink and brown noise are not brand names. They describe how sound energy is spread across the frequency range, and that single difference is why one of them sounds like a hissing television and another like a distant waterfall.
The colours, in one line each
| Colour | Spectrum | Sounds like |
|---|---|---|
| White | Equal energy at every frequency | Untuned radio, hiss |
| Pink | Falls 3 dB per octave | Steady rain, wind in trees |
| Brown | Falls 6 dB per octave | Waterfall, heavy surf, a rumble |
Because we hear pitch logarithmically, white noise puts as much energy in the top octave — 10 to 20 kHz — as in everything below 10 kHz put together. That is why it sounds bright and thin. Pink noise spreads energy evenly per octave instead, which is why it sounds balanced to us. Brown noise rolls off twice as fast and leaves mostly low frequencies.
Brown noise is sometimes written "Brownian noise", after Brownian motion, not the colour. Its other name is red noise.
Which one to use
For sleep, most people who compare all three settle on pink or brown. The reason is duration: high-frequency hiss that is fine for ten minutes becomes fatiguing over eight hours, and the low end is better at covering the sounds that actually wake people — traffic, doors, footsteps upstairs.
For focus, pink and white are the usual picks. The idea is not that noise makes you smarter; it is that a steady background raises the floor, so an unexpected sound is a smaller event and pulls less attention.
For tinnitus, broadband sound is used as masking, and brown is a common choice because it can sit quietly under everything. It does not treat anything. New tinnitus, tinnitus in one ear, or tinnitus with hearing loss or dizziness is a reason to see a doctor, not to download an app.
For a baby, hospitals and paediatric advice tend to converge on the same guidance as for adults: quiet, and not next to the cot.
Why looping tracks stop working
The brain is excellent at detecting repetition, even in something as featureless as noise. A ten-minute rain recording on loop has a seam, and once you have heard the seam — the same gust, the same drip, arriving on schedule — your attention starts waiting for it. That is the opposite of what the sound was for.
There are two honest ways around it. Generate the noise continuously, so there is no recording to repeat. Or take long field recordings and recombine them so the layers never line up the same way twice.
Generated, if you want the colours themselves. Tone Generator produces white, pink and brown noise sample by sample rather than playing a file, so there is nothing to loop. It is a test instrument first — it also does tones from 20 Hz to 20 kHz and sweeps — with an auto-stop after 5, 15, 30 or 60 minutes and a channel switch, so you can send noise to one ear at a time.
Recorded, if you want a whole night. Evermur takes the other route: rain, sea, fire, forest, a summer night and a hypnotic wasp buzz, stitched from real field recordings and reshuffled so the sound never repeats. There is no white, pink or brown mode in it — what it gives you is broadband nature sound whose spectrum sits near pink and brown, plus the slow variation that generated noise does not have. Rain even brings in thunder as you raise the single intensity slider: not louder, just more often.
How loud, and for how long
The volume question matters more than the colour question. A useful rule: if you would have to raise your voice to talk over it, it is too loud for a whole night. Around 50 dB — a soft conversation — is the level most sleep guidance lands on, with the speaker across the room rather than by the pillow.
A sleep timer is the simplest safeguard. Fifteen, thirty or sixty minutes is usually enough to get to sleep, and the room is quiet for the rest of the night.
Nature sound versus generated noise
Rain, surf and wind are broadband sounds whose spectra sit close to pink and brown noise. That is why they work the same way as masking. What they add is slow variation: a shower builds and eases, waves are uneven, a fire crackles at random. For a long night, that variation is usually the difference between a sound you tolerate and one you stop noticing.
Questions & answers
What is the difference between white, pink and brown noise?expand_more
They differ in how the energy is spread across frequencies. White noise has equal energy at every frequency and sounds hissy. Pink noise falls by 3 dB per octave and sounds balanced, like steady rain. Brown noise falls by 6 dB per octave and sounds deep and rumbly, like a waterfall heard from inside a room.
Which noise colour is best for sleep?expand_more
Most people who try all three end up on pink or brown for a full night, because the high hiss in white noise gets tiring over hours. There is no colour that is correct for everyone; the useful test is which one you stop noticing fastest.
Is brown noise good for tinnitus?expand_more
Broadband sound is commonly used to make tinnitus less prominent, and brown noise is a frequent choice because it is low and unobtrusive. It masks rather than treats. If tinnitus is new, one-sided or comes with hearing loss or dizziness, see a doctor.
Why do noise apps sound repetitive after a while?expand_more
Because most of them loop a short recording. The brain is very good at spotting a repeat, and once you hear the seam you cannot unhear it. Continuously generated noise, or long recordings recombined so they never repeat, avoid the problem.
How loud should sleep noise be?expand_more
Quiet enough to talk over. As a rule of thumb keep it around 50 dB — roughly the level of a soft conversation — and never at a volume that would be uncomfortable in daylight. Sleeping every night with loud sound next to your ear is not harmless.
Do I need a noise generator or a nature sound app?expand_more
A generator gives you the colours themselves — white, pink and brown, generated continuously, which is what you want for testing, masking a specific sound or hearing the difference between them. A nature app gives you rain or surf, whose spectra sit near pink and brown but which also vary slowly, and that variation is easier to listen to for a whole night.
Is nature sound the same as noise?expand_more
Rain, waves and wind are broadband sounds with a spectrum close to pink or brown noise, which is why they work in the same way. They also change slowly over time, and that variation is part of why they are easier to listen to for hours.