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Green noise is an informal name for a soft, steady noise centred on the middle of the hearing range. No study has tested it for sleep, so it is not proven to work better than other sounds. It is a sensible choice if white noise feels too sharp: play it quietly, with the speaker across the room, for a few nights before deciding.
What green noise is
White, pink and brown noise each follow a fixed rule for how power changes as pitch rises. Green noise follows no rule. Most sellers use the name for noise that favours the middle of the range, with the very low and very high ends turned down. Some describe it as the background of the outdoors: wind in leaves, a distant stream.
Because nobody owns the definition, two recordings called green noise can sound quite different. One may be a softened white noise; another may be a recording of a forest with a filter on it. The green noise guide covers where the name comes from.
Green noise compared with white, pink and brown
The colours differ in where their energy sits. Measured in Hush between 2 and 12 kHz, as the slope of each sound's level:
| Colour | How it sounds | Where the energy is | In Hush, 2 to 12 kHz |
|---|---|---|---|
| White noise | Bright, hissy, like an untuned radio | Equal at every frequency | White static, +1.6 dB per octave |
| Pink noise | Even and full, like steady rain | Equal in every octave | Velvet noise, −0.2 dB per octave |
| Green noise | Soft, with the hiss taken off | No standard; usually the middle | Green static, −3.2 dB per octave |
| Brown noise | Deep, like distant surf | Mostly low | Deep brown, −3.4 dB per octave |
Does green noise help you sleep?
No study has tested green noise for sleep. Research on sound and sleep has mostly used white and pink noise, and a 2021 systematic review in Sleep Medicine Reviews judged the evidence that steady noise improves sleep to be of very low certainty: some studies found benefits, others none, and most were small.
So choose green noise because you like how it sounds, not because it has been shown to work. Its appeal is what it leaves out. White noise can sound sharp in a quiet bedroom and brown noise can feel heavy; a noise with both softened is easier for some people to leave running.
Green noise benefits: what is claimed and what is known
Benefits listed for green noise usually borrow from claims made for all noise. Here is how they hold up:
| Claim | What is known |
|---|---|
| It covers other noise | True of any steady sound: a constant background makes sudden sounds such as a door or a car stand out less. Green noise does it no better than other noise at the same level. |
| It helps you fall asleep | Not tested for green noise. Evidence for steady noise in general is very low certainty. |
| It is calming because it sounds like nature | A matter of taste. Some people find nature-like sound relaxing; that is a preference, not a measured effect. |
| It helps focus | Not tested for green noise. Studies of noise and concentration are mixed. |
How a green noise measures
Hush files Green static with its white noises. Between 2 and 12 kHz it falls 3.2 dB per octave, where White static rises 1.6 dB per octave. At 12 kHz it sits 9.0 dB further down than White static, relative to each sound's overall level. That missing top end is the softness people describe.
In that same range it falls almost as steeply as Deep brown, which falls 3.4 dB per octave. Hush measures from 2 kHz up, so these figures say nothing about the bass, which is where brown noise is said to differ from green most.
Band by band, in numbers
| Band | Green static | White static | Difference |
|---|---|---|---|
| 2 kHz | −5.2 dB | −7.8 dB | −2.6 dB |
| 2.5 kHz | −6.0 dB | −7.2 dB | −1.2 dB |
| 3 kHz | −6.8 dB | −6.6 dB | +0.2 dB |
| 4 kHz | −8.0 dB | −5.7 dB | +2.3 dB |
| 5 kHz | −8.9 dB | −4.8 dB | +4.1 dB |
| 6 kHz | −9.7 dB | −4.2 dB | +5.5 dB |
| 8 kHz | −11.1 dB | −3.5 dB | +7.6 dB |
| 10 kHz | −12.4 dB | −3.8 dB | +8.6 dB |
| 12 kHz | −13.6 dB | −4.6 dB | +9.0 dB |
Is green noise bad for you?
Not at a comfortable volume. The risk with any sleep sound is loudness, especially for many hours: keep it just loud enough to soften the room, put the speaker across the room rather than by your head, and keep speakers away from babies and young children. The volume guide has a practical level.
How to try it tonight
Give any new sound a fair test:
- Start quietly, just loud enough to soften the room. You should still be able to hear someone speaking normally.
- Put the speaker across the room rather than beside your pillow.
- Set a sleep timer of 30 to 60 minutes with a fade, or let it play all night if you wake when sound stops.
- Use it for three or four nights. Most sounds are easier to ignore once they are familiar.
- Then try pink noise for the same number of nights, and keep the one you notice less.
When another sound may suit you better
If the noise keeping you awake is low, such as traffic, snoring or a neighbour's music, a deeper sound like brown noise covers it better. If it is voices or a television, pink or white noise has more energy where speech sits. If you like something to listen to, rain has a movement that steady noise lacks.
