Green Noise
Short answer
Green noise is a soft, middle sound with no deep rumble and no high hiss, a bit like a stream or a forest in light wind. Unlike white, pink and brown noise, it has no agreed definition. It sounds much the same on a phone speaker as on headphones. But it does little against deep rumble or high sounds.
First, the Honest Part: Green Noise Is Not Standardised
White, pink and brown noise have exact definitions. Each one states exactly how the sound changes from deep to high, and any two versions that follow it sound almost the same. Green noise has nothing like that. No official body defines it in audio, and there is no agreed shape and no agreed centre pitch. Two apps that offer "green noise" can play really different sounds, and neither is wrong, because there is no standard to be wrong about.
The common description, which nearly every page repeats, is that green noise is the middle part of white noise, and that it sounds like the background of the natural world. That description has a real origin, but not the one you might expect. Lau, Arce and Gallagher's Green-noise digital halftoning (Proceedings of the IEEE, 1998; 86(12):2424–2444) introduced green noise as exactly that: the middle part of white noise. But it was a printing method, for arranging dots on paper. Sound apps borrowed the idea from a paper about printing and added a nature story.
So when you compare green noise between apps, you compare different ideas, not versions of one standard. That is why the next section describes ours in full.
Exactly How This Player Makes It
We start with pink noise. Then we make the middle sounds louder, across a wide range, not just one narrow note. Then we cut away the deepest rumble and the highest hiss.
The strongest part sits in the lower middle of the range, and it fades gently on both sides, with no sharp peak. So it still sounds a lot like pink noise, tilted toward the middle. It is not a whistle or a honk. If you heard a "green noise" elsewhere that sounded like a narrow, whistling hiss, that was a different and much narrower idea of the same name.
Because green noise has a shape, not a steady lean from deep to high, we cannot describe it with a single number the way we can for the other colours. Giving one would be dishonest. The description above is the honest version.
What Green Noise Sounds Like
Sounds of nature with both ends taken off. A stream heard from a few metres back, not from the bank. A forest in light wind, without the single leaves. The quiet hum of a large room with a fan somewhere in it. There is no thunder underneath and no hiss on top. What is left is the middle, and most of the sound of the outdoors lives there.
Play it right after brown noise and it sounds like someone opened a window. Play it right after white noise and it sounds like someone closed one. That in-between quality is the whole point. It is the colour for people who find brown noise too muffled and white noise too harsh, and there are a lot of them.
It is also, in our opinion, the least noise-like of the five. Brown and white both sound made by a machine. Green noise sounds more like a place.
What Green Noise Is Genuinely Good At
Phone and laptop speakers. This is green noise's real advantage, and it is a practical one. Small speakers cannot play deep sounds well, which ruins brown noise. Cheap speakers also often sound harsh at the top, which makes white noise worse. Green noise has almost no very deep sound and almost no very high sound, the two areas small speakers handle worst. It is the one colour on this site that sounds much the same through a phone speaker as through headphones. If you do not want to sleep in headphones and do not own a good speaker, start here.
The middle ground between brown and white. If you tried both and found brown noise too heavy and white noise too sharp, green noise is a better next step than pink. It does not just sit between them. It removes both of the things you disliked.
Covering the body of speech. Green noise is strongest in the range where the main sound of a voice sits. It turns "someone is talking in the next room" into something closer to "there is a room next door". For many people, that is the part that grabs their attention.
Daytime background. It does not draw attention the way brown noise does. Brown noise announces itself with weight. Green noise mostly just fills the room.
What Green Noise Is Bad At
Both ends, on purpose. We removed the deepest and the highest sounds on purpose. So green noise does almost nothing against traffic rumble, air conditioning or a heating system, footsteps overhead or a neighbour's bass. For those, use brown noise. It also does almost nothing against a whining laptop, a squealing fan or other high-pitched noises. For those, use white or blue noise. Green noise is a specialist, and that cuts both ways.
Consonants, so it cannot fully hide speech. It covers the body of a voice, but it leaves the consonants, the sharp sounds such as "t" and "s", mostly untouched. Consonants are what make words clear. If you can still make out single words through green noise, that is why. White noise is the right fix.
Voice calls and talking. Green noise is strongest where your own voice is strongest. Some people feel it competes with them when they talk, read aloud or are on a call. Brown noise never does that.
Evidence, of any kind. This is not a case of thin research. There is none. No study has tested green noise for sleep, focus, tinnitus or anything else. None really can while the term has no agreed definition, because there would be no fixed sound to test. The 2021 systematic review of noise as a sleep aid looked at steady white noise and similar noise, and rated the evidence overall as very low quality. Green noise was not in it at all. Anyone who claims medical support for green noise is making it up. Nothing here is medical advice.
Using It Well
Test it on the speaker you will really use. The case for green noise depends more on the speaker than for any other colour. Testing it on good headphones and then using it on a bedside phone tests the wrong thing. If you plan to use your phone, judge it on your phone.
Compare it with pink, not with brown. Green noise is built from pink noise, so pink is its nearest neighbour and the more useful comparison. If pink already sounds right, green will sound like pink with the ends trimmed. If pink sounds a little hissy, green is the fix.
Web player and app. The browser player runs free 30-minute sessions with nothing to install. The app has green noise next to brown, white, pink and blue, with no session limit, a sleep timer, offline playback and the option to add rain or thunder on top. That suits green noise well, because it leaves the high sounds free for the rain.
How It Compares With the Other Colours
Four of the five colours line up from deep to bright: brown is the deepest, then pink, then white, then blue. Green noise is not on that line at all. It is a shape, not a lean: a hump in the middle with both ends taken away. That is why it cannot be described with one number, and why it fills a gap the other four leave open.
Think of it less as a point on a scale from deep to bright, and more as a different question. Not "how bright do you want it?" but "what if we removed everything except the part you actually hear?"
Frequently Asked Questions
What pitch is green noise?
There is no standard answer, and that is the important point. The common description puts it in the lower middle of the range we hear. This player follows that: pink noise with a wide boost to the middle sounds, and with the deepest rumble and the highest hiss cut away. Another app's green noise may be centred somewhere else, or be much narrower.
Why does green noise sound different in different apps?
Because there is no standard for it. White, pink and brown noise each have an exact definition, so different versions sound alike. Green noise has only a loose description: the middle part of white noise. That leaves the centre pitch, the width and the size of the boost up to whoever makes it. When you compare green noise across apps, you compare different ideas, not versions of one standard.
Is green noise better than brown noise for sleep?
Neither is better in general, and no research compares them. They solve different problems. Brown noise is much better against low noises such as traffic and machines, and works best through headphones or a speaker that plays good bass. Green noise does nothing about those. But it sounds almost complete on a phone speaker, and avoids the muffled feel some people dislike in brown noise. Choose by what disturbs you and what you will play it on.
Is green noise the sound of nature?
That is the marketing description, not a measurement. What is true is that green noise is strongest in the middle range, where much outdoor sound sits: moving water, wind in leaves, sounds in the distance. It also removes the deep rumble and the high hiss that make a sound seem artificial. So it reminds people of nature more easily than white noise does. It is not a recording of anything.
Is there any research on green noise?
None. Not thin evidence: none at all. No published study has tested green noise for sleep, focus or tinnitus. It is hard to see how one could while the term has no agreed definition, because there would be no fixed sound to test. The reviews that exist look at steady white noise and similar noise, and rate that evidence as very low quality. Any page that claims medical support for green noise is inventing it.
Why does green noise sound better than brown noise on my phone?
Because we built it to. Phone speakers cannot play much of the deep sound, and that is where nearly all of brown noise is. So a phone plays only a small part of brown noise. Green noise has its deepest and highest sounds cut away on purpose. So it avoids both the range small speakers cannot play and the range where cheap speakers sound harshest. It is the colour that loses least on a basic speaker.