White, pink, or brown noise: which is actually best for sleep?

Go looking for sleep sounds and the colors show up right away. White noise, pink noise, brown noise, sometimes green or blue too, and every one of them comes with somebody swearing it’s the one that finally worked. It’s a lot less complicated than it looks, and once you know what the colors mean, picking one gets a lot easier.

What the colors mean

All three are the same basic thing: a steady, random hiss with no rhythm and no melody. The only difference is how the sound is spread out between the low end and the high end.

White noise has the same energy at every frequency. To your ears that comes across bright and hissy, because we’re more sensitive to the higher pitches and there are a lot more of them. Think TV static, or a radio stuck between stations.

Pink noise rolls the high end off gradually, so it sounds softer and fuller. It’s closer to steady rain, or wind going through the trees.

Brown noise rolls the high end off even more. (It’s named after Robert Brown, the Brownian motion guy, not the color.) It’s deep and rumbly, like distant surf, a strong wind, or the inside of an airplane.

So pink and brown aren’t really different kinds of sound. They’re white noise with more and more of the treble taken out.

Why any of them help

The big thing a steady sound does is masking. What wakes you up usually isn’t loud noise. It’s change. A car door, the dog, somebody snoring, the furnace kicking on. Your brain keeps half an ear open while you sleep, and it flags anything new.

A steady sound raises the background, so those sudden changes don’t jump out as much. The car door still happens. It just isn’t a spike out of total silence anymore. That’s also why the sound has to be steady. Anything with a rhythm, a melody or a loop you can hear gives your brain something new to notice, which is the exact opposite of what you want.

What the research says (and doesn’t)

The evidence is thinner than the internet makes it sound.

Masking itself makes sense, and plenty of people find a steady sound helps them fall asleep and stay asleep, especially somewhere noisy.

Pink noise has the most interesting research, but a lot of it is small studies, and some of the best-known ones didn’t leave a sound running all night at all. They played short bursts of pink noise timed to the sleeper’s own brain waves. In one study of older adults, those timed bursts deepened slow-wave sleep. Cool, but not the same as a sound machine on your nightstand.

And a 2021 review that pulled together the studies on continuous noise as a sleep aid rated the evidence as very low quality. That doesn’t mean it doesn’t work. It means it hasn’t been studied well, and nobody’s shown that one color beats the others for everybody. The authors also point out that loud noise all night can mess with your sleep and your hearing on its own, which is one more reason to keep the volume down.

So there’s no good evidence you need a particular color. The best one is probably whichever one you find easiest to tune out.

How to pick

If high, hissy sounds bug you, skip white noise and try something deeper. A lot of people who “hate white noise” end up loving brown noise.

If you’re trying to cover voices or a TV through the wall, something fuller in the middle, pink-ish like steady rain, usually covers speech better than something really deep.

If it’s low rumbles you’re fighting, traffic or the neighbor’s bass, a deeper sound like ocean surf matches them better.

And give it a few nights. Any new sound is noticeable at first, which is the last thing you want at bedtime. It takes a little while to fade into the background.

Where rain and ocean sounds fit in

Natural sounds have colors too, more or less. Steady rain and a babbling brook land pretty close to pink noise. Ocean waves, distant surf and strong wind lean brown. A fan or a clothes dryer is a big, even whoosh. That’s why so many people sleep fine to them. They do the same masking job, they just don’t sound like static.

That’s the way I went with Repose. There’s no synthetic noise in the app. There are 25 recorded sounds instead, from Steady Rain and Heavy Rain to Deep Ocean Waves, Distant Waves, Ocean Wind and an Oscillating Fan, and you can layer them and set each one’s volume. Want something pink-ish? Start with rain. Brown-ish? Try the deeper ocean sounds or the wind. Every loop is gapless, too, so there’s no little click every half minute undoing all that masking.

A few practical things

Keep it quiet. It only has to be loud enough to soften sudden noises, not drown out the world. About the level of a quiet conversation is plenty for most rooms, and quieter is fine.

Put the phone or speaker across the room, not on your pillow.

With babies, be even more careful. Keep it well away from the crib, and keep it low. A study of infant sleep machines found some of them could get loud enough at full volume, sitting close by, to be a real concern for a baby’s hearing.

And you don’t have to leave it on all night. If the sound helps you fall asleep but you’d rather wake up to quiet, a sleep timer that fades out slowly gets you both. (Repose’s does, at 15, 30, 60 or 90 minutes.)

None of this is medical advice. If you’re having trouble sleeping on a regular basis, talk to your doctor. But if you’re just trying to tune out a loud street or a snoring partner, the color matters a lot less than finding a steady sound you like enough to forget is on.