--- title: "What Is Green Noise? Sound, Sleep and How It Compares" description: "Green noise is an informal name for steady noise centred on the middle frequencies, around 500 Hz. It has no standard definition and no sleep studies yet." url: https://shimmr.app/learn/green-noise/ --- - [Learn](https://shimmr.app/learn/) - [Guides](https://shimmr.app/learn/guides/) # What is green noise? How it sounds and if it helps sleep Green noise is an informal name for steady noise centred on the middle frequencies, around 500 Hz. It has no standard definition and no sleep studies yet. The Shimmr team Published Oct 31, 2026 4 min read - **What it is:** green noise is an informal name for steady, broadband noise with most of its energy in the middle of the range we hear, often described as around 500 Hz. - **No standard definition:** unlike white, pink and brown noise, green noise has no agreed technical recipe, so two green noise tracks can sound quite different. - **How it sounds:** softer than white noise and less deep than brown noise, which is why people compare it to a distant waterfall or wind in trees. - **Evidence for sleep:** no study has tested green noise for sleep, and a 2021 systematic review of 38 studies rated the evidence that steady noise improves sleep as very low quality. - **Safe use:** keep the volume low, quieter than normal conversation at about 60 dB, and use a sleep timer if you only need it to fall asleep. Hear it Green noise is a steady sound with most of its energy in the middle of the range we hear, often described as around 500 Hz. If you have wondered what green noise is after seeing it on TikTok, the short answer is: a softer, more natural sounding cousin of white noise, with no standard definition and no sleep studies of its own yet. Here is how it sounds, how it differs from the other colours, and what the evidence says. ## What is green noise? Green noise is an informal name for broadband noise that is strongest in the middle frequencies. Broadband means it covers a wide spread of pitches at once, like a fan or rain, rather than a single tone. The name follows the other [colours of noise](https://shimmr.app/learn/colors-of-noise/). White noise has equal energy at every frequency. Pink and brown noise tilt that energy toward the low end. Green noise puts a bump in the middle, and the figure you see most often is around 500 Hz, roughly the pitch of the B above middle C on a piano. The key thing to know: white, pink and brown noise have exact mathematical definitions. Green noise does not. It is a label used by apps, playlists and sound designers, so two tracks both called green noise can sound different. ## What does green noise sound like? Green noise sounds softer than white noise and lighter than brown noise. Because the very high and very low frequencies are turned down, there is less hiss and less rumble. People often compare it to: - wind moving through trees - a waterfall heard from a distance - the steady background of the outdoors Some say it sounds more natural than other noise colours. That is a matter of taste rather than science, but it explains much of its popularity. ## Green noise vs brown, pink and white noise The colours differ in where the energy sits. This table shows how they compare: | Colour | Where the energy sits | Sounds like | Defined exactly | | --- | --- | --- | --- | | White | Equal at every frequency | Hiss, TV static | Yes | | Pink | Falls by 3 dB per octave | Steady rain | Yes | | Brown | Falls by 6 dB per octave | Deep rumble, distant thunder | Yes | | Green | Peak in the middle, around 500 Hz | Wind, far waterfall | No | An octave is a doubling of pitch, and 3 dB is about half the energy. For a closer look at the two most popular colours, see [brown noise vs white noise](https://shimmr.app/learn/brown-noise-vs-white-noise/), and for the research on rain-like noise, our guide to [pink noise for sleep](https://shimmr.app/learn/pink-noise-for-sleep/). ## Is green noise good for sleep? Green noise may help you fall asleep, but no study has tested it directly. A search of the research finds the phrase “green noise” mostly in image processing, where it means something else entirely. What we do have is research on steady noise in general: - A [2017 randomised trial](https://doi.org/10.3389/fneur.2017.00718) of 18 healthy adults played steady broadband sound at about 46 dB in a sleep lab bedroom. They went to bed 90 minutes earlier than usual, a set-up designed to make falling asleep hard. With the sound, the time it took them to reach stage 2 sleep, the first stage of steady sleep, fell by a median of 38% compared with normal room noise. - A [2021 systematic review](https://doi.org/10.1016/j.smrv.2020.101385) of 38 studies found results ranging from better sleep to worse sleep. It rated the evidence that steady noise improves sleep as very low quality and said it may also affect sleep and hearing. So green noise is likely to work the way other steady noise works: it masks sudden sounds like traffic or a door, so they are less likely to wake you. Whether its middle-heavy sound is better than pink or brown has not been studied. Our guide to [sleeping with white noise](https://shimmr.app/learn/sleeping-with-white-noise/) covers how to set up any noise colour for the night. ## Is green noise good for focus or ADHD? There is no research on green noise and focus or ADHD. Claims you may see online come from personal experience, not studies. Some people do find a steady, mid-range sound easier to work with than music, because it has no words or melody to pull their attention. If you want to try it, start at a low volume and give it a few work sessions before you decide. If you have ADHD, talk to your doctor about treatments that are known to help; noise can be a comfort, not a replacement. ## How to listen to green noise safely Keep the volume low and give your ears breaks. A good guide is to stay quieter than normal conversation, which is about 60 dB. If you can hear it clearly over your own breathing but it does not drown out a quiet voice, you are in a sensible range. A few simple tips: 1. Play it from a speaker across the room rather than headphones if you sleep with it. 2. Use a sleep timer with a fade if you only need help falling asleep. 3. Try it for a week before you judge it; any new sound can feel odd for the first few nights. In Shimmr, green noise sits in the library next to white, pink, brown and orange noise. You can play it on its own or layer it under a Shift or rain in the mixer, then let the sleep timer fade everything out. - [White noise app White noise, without the ads. And without needing a signal.](https://shimmr.app/white-noise-app/) In the app Awake → Asleep · 20 to 90 min Play this Shift and layer green noise underneath in the mixer, then let the sleep timer fade both out. ## Common questions **What is green noise?** Green noise is an informal name for steady noise with most of its energy in the middle frequencies, often described as around 500 Hz. It has no standard scientific definition, unlike white, pink or brown noise. **Is green noise good for sleep?** It may help some people the way other steady noise does, by masking sudden sounds. No study has tested green noise itself, and the evidence for steady noise and sleep in general is rated very low quality. **What is the difference between green noise and brown noise?** Brown noise puts most of its energy in the low frequencies and sounds like a deep rumble. Green noise sits in the middle frequencies, so it sounds lighter and more open, closer to wind or a far-off waterfall. **Is green noise good for focus or ADHD?** There are no studies on green noise and focus or ADHD. Some people like it as a steady background while they work; if you have ADHD, talk to your doctor about what is known to help. **Is green noise safe to listen to all night?** For most adults, yes, if the volume is low, quieter than normal conversation. A 2021 review warned that steady noise all night may also disturb sleep or hearing, so a sleep timer with a fade is a careful choice. Keep reading - [Guides Brown noise vs white noise (and pink and green): which to use](https://shimmr.app/learn/brown-noise-vs-white-noise/) - [Sleep Pink noise for sleep: what the studies really show and how loud to play it](https://shimmr.app/learn/pink-noise-for-sleep/) - [Sleep Is it bad to sleep with white noise every night?](https://shimmr.app/learn/sleeping-with-white-noise/) This article is for general information and is not medical advice. Binaural beats are not a treatment for insomnia or any other condition.