Brown Noise

What Brown Noise Actually Sounds Like

Brown noise is the deepest of the common noise colours. Most people describe it with water: a strong waterfall, a river in flood, or waves heard from the top of a cliff. Others hear machines: the hum inside a plane on a long flight, a tumble dryer two rooms away, or wind pushing on a window at night. All of these sounds are low and heavy, with almost no hiss on top.

Next to white noise, the difference is clear. White noise seems to come from one point in front of you. It is bright, papery and a little rough. Brown noise seems to come from the whole room. That wrapped-around feeling is why many people pick it for a full night, not a short session. It is also why people who disliked white noise often like brown noise straight away.

The player above makes brown noise live, as you listen, instead of playing a recording on repeat. So there is no point where the sound starts again. There is nothing to notice at three in the morning, and nothing to start listening for.

How Deep Is It? We Checked

Brown noise is also called Brownian noise or red noise. It gets steadily quieter as the pitch goes up, in a fixed pattern. Most pages repeat this definition. Few of them check that their own sound actually does it.

We measured ours. The sound gets steadily quieter as the pitch goes up, exactly as true brown noise should, and it stays very close to the ideal all the way up.

In everyday terms, almost all of the sound is at the bottom. In the middle range, where the vowels of normal speech sit, brown noise is already much quieter. In the high, hissy range there is very little left. That one fact explains what brown noise is good at, and what it is bad at.

What Brown Noise Is Genuinely Good At

Low, rumbling noise. Traffic rumble, air conditioning or a heating system, a lift motor, bass from a neighbour's music, footsteps on the floor above. A steady sound covers best when it is at the same pitch as the noise you want to hide. So a low noise needs a low sound to cover it. Brown noise is the only colour on this site with real power in the very deepest sounds. For these problems, nothing else here comes close.

Long sessions. Brown noise has almost no high, hissy sound. That is why people can leave it on for eight hours without it starting to grate. The tiring part of most noise is the hiss, and brown noise has very little of it.

People who dislike white noise. If white noise felt sharp, tinny, or like a hiss inside your head, try brown noise next. It is the same idea at the opposite, deep end.

Mixing with other sounds. Because it sits so low, brown noise fits under rain, music or a fan without fighting them. In the app, this is what sound mixing is for: brown noise underneath, with rain or thunder on top.

What Brown Noise Is Bad At

It cannot cover high sounds. A smoke alarm's low-battery chirp, a phone notification, birdsong at dawn, the hiss of speech through a wall: brown noise has almost nothing at that pitch. If a conversation keeps you awake, not a lorry, white or green noise will help more. Turning brown noise up will not change that.

It needs a speaker that can play deep sounds. Phone speakers, laptop speakers and small Bluetooth speakers cannot play very deep sounds well. That is exactly where most of brown noise is. Through them, much of the sound is simply missing, and turning the volume up does not bring it back. Headphones or a bigger speaker change the sound so much that you should test them before you give up on brown noise.

It travels. Low sounds pass through walls, floors and doors much more easily than high sounds. That is why you hear a neighbour's bass but not their words. If you live in a flat, or share a wall with a light sleeper, brown noise is the colour most likely to bother someone else.

Deep sound all night does not suit everyone. Some people feel pressure or fullness in the ears after a while. If that happens to you, pink noise has a similar calm feel with much less weight at the bottom. Green noise removes the deepest sounds completely.

What the Research Does and Does Not Show

The honest position is that there is almost no research on brown noise itself. Pages that suggest otherwise are overselling.

The most useful review is Riedy and colleagues, Noise as a sleep aid: A systematic review (Sleep Medicine Reviews, 2021). It looked at 38 articles on steady white noise and similar noise as a sleep aid. It did not give the strong support people often claim. It judged the evidence that steady noise improves sleep to be of very low quality, and some of the studies found no benefit or worse sleep. None of the studies tested brown noise on its own.

The other study people often quote is about different colours and a different question. Nigg and colleagues (Journal of the American Academy of Child and Adolescent Psychiatry, 2024) combined the results of trials on white or pink noise and attention tests in a lab. They found a small benefit for people with ADHD or many ADHD symptoms, and no benefit for anyone else. Again, brown noise was not tested.

What is not in doubt is how sound masking works. Sound masking means covering one sound with a steadier one, so your brain stops noticing it. A steady sound makes other sounds at a similar pitch harder to hear, and brown noise is very well suited to covering low household noise. Whether covering noise leads to better sleep is a different question. Nobody has answered it well for any colour, and almost nobody has asked it for brown noise.

So if brown noise works for you, use it. It is free, it is not a drug, and at a sensible volume it has no obvious downside. But be sceptical of any page, or any app store listing, that calls it clinically proven. Nothing here is medical advice. If a sleep problem does not go away, talk to a doctor, not to a noise generator.

Getting the Most Out of It

Set the volume by the noise you want to cover. Turn it up only until that noise stops being clear, then stop. More volume after that point covers nothing more. It only adds to what your ears take in. A good rule: if you could still talk over it without raising your voice, the level is sensible.

Where you put the speaker matters less than usual. It is hard to tell where low sounds come from. So a speaker on the floor, behind a chair or across the room works about as well as one by your head. With white noise it is the opposite: you can clearly hear where the speaker is.

All night or on a timer. The web player is free in 30-minute sessions. That is enough to fall asleep to, but not enough for a whole night. The app removes the session limit and adds a sleep timer, offline playback and play in the background. Most people want that once they know the sound suits them.

How It Compares With the Other Colours

Brown noise is at one end of the noise colours. Think of the others as a slider from dark to bright. Pink noise is halfway: still warm, but with some of the detail that brown noise loses. White noise is flat and bright, and by far the most studied. Green noise keeps the middle sounds and drops both ends, so it sounds much the same on a phone speaker as on headphones. Blue noise leans the other way, towards high sounds, and is used more in technology than for sleep.

If your problem is rumble, start here. If your problem is voices, start with green or white. If you are not sure, pink is the safest default.

Frequently Asked Questions

Related pages

• Brown Noise for Sleep — The free web player, plus the full guide to brown noise for sleep, focus, and tinnitus.
• Noise Colour Test — Two questions and a listening test to find your noise colour.
• Sleep Calculator — Find the best time to go to bed or wake up, in 90-minute sleep cycles.
• Pink Noise — The balanced, natural-sounding colour: a good default, and the sound engineers use to test speakers.
• Brown Noise Generator — A real brown noise generator in your browser: made live as you listen, with no file and no loop.
• White Noise — The flat, bright colour, and the best of the five at making speech impossible to follow.
• Green Noise — The middle colour: pink noise with the middle sounds made stronger, and the only one of the five with no standard definition.
• Blue Noise — The bright end of the colours: useful against high-pitched noise, but a poor choice for sleep.
• Brown Noise for Tinnitus — Masking versus getting used to tinnitus, why the pitch of your tinnitus decides the colour, and where sound therapy really sits in the 2014 medical guideline.
• Brown vs White Noise — The two colours furthest apart: what each one can and cannot cover, and why your speaker may decide for you.
• Brown vs Pink Noise — Almost the same in the deep sounds, far apart in the high ones, and one of them falls apart on a phone speaker.
• Brown Noise for ADHD — A 2024 review found a small benefit from white and pink noise on lab attention tasks in ADHD, a small drop without ADHD, and no studies of brown noise.
• Brown Noise for Focus — Why focus is mostly about blurring speech you can follow, and why brown noise beats every colour for rumble but loses to white for voices.
• Brown Noise for Babies — The 2014 Pediatrics measurements first: all fourteen infant sleep machines tested were louder than the nursery noise limit at 30 cm. What that means for volume, distance and time.
• Brown Noise App — Which brown noise app to install, whether it is really free, and what an app can do that a browser tab cannot.
• Sound Masking — Masking does not block sound. It raises the background so the noise stops standing out, and the colour has to match the noise.
• Block Traffic Noise — Your walls already removed the high sounds from the traffic outside. That is why brown noise covers it indoors and white noise does not.
• Brown Noise Machine — Two very different products are sold as a brown noise machine, and one of them cannot make brown noise. What to check before buying.
• About — Who publishes this site, how we check what we write, and how we handle health topics.