The difference between white, pink and brown noise is how the sound's energy is distributed across frequencies: white noise is flat, pink noise falls 3 dB per octave, and brown noise falls 6 dB per octave. In listening terms, white sounds like static, pink like rain, and brown like distant thunder or surf. Each is made from the one before by rolling off more of the high end.
All three are available in the free generator on this page, along with blue, violet and grey, and a slider that blends smoothly between them. The site has no ads, no signup and no tracking, the code is open source, and the noise is synthesized in your browser by the Web Audio API so it never loops. Try each for a minute in turn; the difference is obvious once heard.
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| Color | Spectral slope | Sounds like | Best for |
|---|---|---|---|
| White | Flat, 0 dB per octave | TV static, untuned radio, a hiss | Masking voices and high-pitched sounds, tinnitus |
| Pink | Minus 3 dB per octave | Steady rain, a waterfall, wind in trees | Focus, general sleep, speaker calibration |
| Brown | Minus 6 dB per octave | Distant thunder, surf, an airplane cabin | Sleep, long sessions, ADHD focus, low rumble masking |
Each row down the table has half as much high-frequency content, relatively speaking, as the one above it. That single variable, the slope, accounts for everything people notice about the three sounds: how bright or deep they seem, how tiring they are over hours, and which outside sounds they cover best. Everything else, such as pulses, textures and EQ, is added on top.
Every noise color is described by a power spectral density of the form 1/f to some power alpha. White has alpha equal to 0, so the power is the same at every frequency. Pink has alpha equal to 1, so power halves each time frequency doubles, which is minus 3 dB per octave. Brown has alpha equal to 2, so power falls to a quarter per doubling, minus 6 dB per octave. Blue and violet continue the series in the other direction with negative alpha.
The reason white noise sounds bright even though it is flat is that hearing is logarithmic. The octave from 5 to 10 kHz contains ten times as many hertz as the octave from 500 Hz to 1 kHz, so it collects ten times the power. Pink noise, with equal power per octave, is the one that sounds balanced. The full treatment with equations is on the physics page.
Start with Pure White. It is a sharp, even hiss with a slightly metallic edge, and after a minute most people are aware of it as a presence in the upper midrange. Switch to Standard Pink and the hiss drops back, the sound gains body and it stops feeling like it is coming from one place; it is now rain. Switch to Deep Brown and the hiss is almost gone, leaving a low roll that is felt as much as heard.
A useful test is to turn the volume down until each is barely audible. White noise becomes a thin whisper. Pink noise stays recognizably rain-like. Brown noise turns into something like a room's air handling, felt more than heard. That is a preview of how each behaves at the low volume you will actually use at night.
For sleep, brown or pink. Brown is deeper and covers low-frequency intrusions such as traffic and neighbors' bass; pink covers voices and footsteps a little better. Neither has been shown in controlled studies to produce better sleep than the other, so preference decides. The sleep page has presets built around both.
For focus, pink or a pink-brown blend is the common choice, because it covers the speech range without fatiguing. White noise masks voices most efficiently per decibel but wears on many people after an hour. For tinnitus and other high-pitched sounds, white or the brighter blue is usually the better match. For a fan-like or machine-like sound at any hour, grey noise applied to any of the three keeps the balance even at low volume.
The three named colors are points on a line, not separate things, and the generator treats them that way. The color slider runs from 0 to 4: 0 is violet, 1 is blue, 2 is white, 3 is pink and 4 is brown. A value of 3.5 is halfway between pink and brown, with a slope of about minus 4.5 dB per octave, and it happens to be one of the most popular settings on the site; several focus and mechanical presets sit there. Layered Depths goes further and plays brown and blue at once for a two-layer sound.
Under the hood all of them begin as white noise. Pink is white passed through the Paul Kellett filter bank; brown is white integrated sample by sample with a leak to stop it drifting; blue and violet are white differentiated. Fractional slider positions crossfade between the neighboring algorithms. The result is continuous and non-repeating, and you can save any point on the line as a shareable URL or export it as a WAV.
Yes. Both roll off toward high frequencies, but brown does so twice as steeply, 6 dB per octave versus 3 dB. Brown noise has almost no audible hiss and sounds like distant thunder or surf, while pink noise keeps a rain-like hiss on top. White noise is the brightest of the three with no roll-off at all.
Most people prefer brown or pink because their energy sits in low frequencies that feel calming, and white noise's hiss can be alerting. There is no research showing one color improves sleep more than another. Play each at the same low volume for a few nights and keep the one you notice least.
Not at the same output level, but it sounds different. White noise puts its perceived loudness in the treble and can seem sharper, so people often turn it down; pink spreads its loudness evenly and can feel fuller at the same setting. Compare them at the same volume position rather than adjusting between switches.
Yes. The color slider blends continuously between them, so 2.5 is half white and half pink, and 3.5 is half pink and half brown. The Layered Depths preset plays two colors at once for a two-layer sound, and custom presets can combine any two. The grey toggle can be added to any of them.
White and pink come from light: white light contains all wavelengths equally, and light tilted toward the long-wavelength red end looks pink. Brown is different; it is named after Robert Brown, whose Brownian motion has the same random-walk mathematics. Brown noise is sometimes called red noise to keep the color analogy consistent.