The noise colours at a glance
White, brown, and pink noise are all steady, random background sounds; they belong to one family named after the colours of light, by analogy with how white light contains every colour mixed together.1 What sets them apart is not what they do but how they sound, and that comes down to where each one puts its energy across the range of pitches. A frequency is just how fast a sound vibrates, measured in hertz (written Hz); low frequencies are deep, rumbling tones and high frequencies are bright, hissy ones. White noise spreads its energy evenly across every pitch, so it sounds bright and full. Brown noise piles its energy into the low pitches, so it sounds deep and soft. Pink noise sits between the two, gently weighted toward the deeper end, so it sounds balanced and rounded. That single idea, the tilt of energy from bright to deep, is the whole difference, and the table below lays it out at a glance.
| Colour | Energy across the pitches | How it sounds | Commonly used for |
|---|---|---|---|
| White | Flat: equal energy at every pitch2 | Bright, full hiss (like static) | Masking sudden noises; general cover |
| Pink | Falls gently, about 3 dB per octave (1/f)3 | Softer, balanced, like steady rain | Relaxing; a gentler masking sound |
| Brown | Falls steeply, about 6 dB per octave4 | Deep, low rumble (like distant thunder) | Calm; deep background for focus or sleep |
Read the table top to bottom and you are really watching one dial turn: from the even brightness of white, through the balanced middle of pink, down to the deep rumble of brown. Everything else in this comparison follows from that.
These three are the colours you will actually meet in apps and sleep machines, but the family is larger, and there are rarer colours such as green, blue, and grey. For the full map of how all the noise colours are defined and where each is used, see our plain-English guide to the colours of noise.
White noise vs brown noise
This is the most-asked matchup, and it is the clearest contrast of the three: the bright hiss against the deep rumble. White noise is the reference colour, defined by the Acoustical Society of America as noise whose energy is essentially independent of frequency across a stated range, meaning it carries roughly the same energy at every pitch.2 That even, full spread is why it sounds like static or an untuned radio: bright, and a little harsh to some ears. Brown noise (also called Brownian or red noise) does the opposite, with its energy falling steeply as the pitch rises, by about 6 decibels per octave (a decibel is the standard unit of loudness, and an octave is a doubling of pitch), which gives it a low, soft roar resembling heavy rain, a distant waterfall, or far-off thunder.4
The practical trade-off is straightforward. Because white noise covers the whole range of pitches evenly, it tends to mask a wide variety of intrusive sounds, which is why it became the default cover sound for offices and nurseries. Brown noise, being weighted to the deep end, is especially good at blunting low rumbles such as traffic or a humming appliance, and many people find its bassy tone gentler to have on for hours than white noise's bright hiss. Neither is doing anything magical: both work by masking, covering up sudden or distracting sounds, and the choice between them is mostly about which tone you find more comfortable. For the full detail on each, read our complete guide to white noise and our complete guide to brown noise (each publishes when that guide ships).
White noise vs pink noise
If white noise feels a touch too bright for you, pink noise is the natural step toward something softer without going all the way to a deep rumble. Pink noise is defined by the Acoustical Society of America as noise whose energy varies as the inverse of frequency, often written 1/f, so its energy falls gently as the pitch rises, by about 3 decibels per octave.3 That is a gentler slope than brown noise's, which is why pink sits in the middle: softer and rounder than white, but not as deep and bassy as brown. People often compare it to steady rainfall, where white noise is closer to static.
In use, the difference between white and pink is subtle and almost entirely about feel. Both mask sudden noises across a broad range, but pink takes some of the edge off the high pitches, which human hearing is especially sensitive to, so many people find it more comfortable over a long stretch. That comfort is a perfectly good reason to prefer it; it is not that pink noise is secretly more effective. Some people still favour the crisper hiss of white, and neither preference is wrong. The honest point is that white versus pink is a matter of taste, not of one colour beating the other. For the detail on each, see our complete guide to white noise and our complete guide to pink noise (each publishes when that guide ships).
Brown noise vs pink noise
Brown and pink are the two softer colours, both tilted away from the bright hiss of white, so this pairing is about how deep you want to go. Both fall in energy as the pitch rises, but brown falls about twice as steeply as pink, roughly 6 decibels per octave against pink's 3.43 That steeper fall is what makes brown sound like a deep, full rumble while pink sounds like balanced, even rain. If you find pink pleasant but want something heavier and more enveloping, brown is the next step down; if brown feels too heavy or muffled, pink is the lighter, more open-sounding choice.
As with every pairing here, the difference is tone, not effect. Both mask other sounds in the same basic way, and both are popular for relaxing, sleep, and background focus. Which one suits you depends on whether you prefer a balanced wash or a deep rumble, and on what you are trying to cover: brown's low weight can be better against deep, droning noises, while pink's broader balance can feel more natural in a quiet room. There is no evidence that either one is generally better; it is genuinely down to your ear. Read our complete guide to brown noise and our complete guide to pink noise for the full picture on each (each publishes when that guide ships).
Which colour for sleep or focus?
The most common reason people compare the colours is to settle the "which is best for sleep or focus" question, so it is worth being honest up front: there is no single proven answer, only sensible starting points and a lot of personal variation. The plain reason is that the head-to-head evidence is thin. The careful research on noise and attention is mostly about white noise, not brown or pink, and it shows the effect is far from universal: a 2023 study in Frontiers in Psychology of children grouped by ADHD-symptom level found that white noise tended to help those with more attention difficulties while doing little for those whose attention was already good.5 On sleep, a systematic review in Sleep Medicine Reviews that gathered the studies on continuous noise as a sleep aid found the overall quality of the evidence was very low, with continuous noise able to improve or disrupt sleep depending on the study; the authors said more rigorous research is needed before it is promoted as a sleep aid.6 So no colour has been shown to beat the others for either purpose. As a rough starting point, many people gravitate to the softer, deeper colours (pink or brown) at bedtime and try a steadier background for focus, but that is preference, not proof. For the full verdicts, see our guides to the best noise colour for sleep and the best noise colour for focus; and if your interest is noise and attention difficulties, our guide to sound therapy and ADHD covers that properly (each publishes when that guide ships).
How to choose
Because the colours differ in tone rather than effect, the most reliable way to choose is also the simplest: try them and go by your own ear. Play white, pink, and brown for a minute each and notice which feels most comfortable for what you are doing, then give your pick a few sessions before judging it. There is no wrong answer, and your preference may even change with the task or the time of day. This fits what national health bodies say about sound and wellbeing in general: music-based and sound-based approaches show genuine promise for things like relaxation and sleep, but many studies are small and more rigorous work is needed before strong claims are warranted.7 Whichever colour you settle on, keep the volume low; the goal is a soft blanket of sound that blurs sudden noises, not a wall of it, and gentle is just as effective as loud while being far kinder to your hearing. The World Health Organization advises that listening at around 80 decibels is safe for up to about 40 hours a week, with the safe time falling sharply as the volume rises.8 Sonora takes a different approach from a single fixed colour, matching adaptive sound to you and the moment; you can try Sonora free to hear how that feels, and you can see the full citation list behind Sonora's claims on Sonora's evidence base.
