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Pink noise has equal power in every octave, so it sounds fuller and softer than white noise. The studies behind its reputation played short bursts of it, timed to brain waves during deep sleep in a lab, not steady noise all night. For ordinary use it has not been shown to work better than other sounds, but many people find it easier to listen to than white noise.
What pink noise is
Pink noise carries the same power in every octave, so low and high pitches get an equal share. It sounds fuller than white noise and less hissy, close to steady rain or wind in leaves. White noise, by contrast, has the same power at every single frequency, and because each higher octave holds twice as many frequencies, it sounds bright. Pink noise, measured shows the five versions in Hush.
What the studies tested
The best-known results come from sleep labs. In a 2013 study in Neuron, researchers recorded sleepers' brain activity and, during deep sleep, played short bursts of pink noise timed to the peaks of their slow brain waves. Those waves grew stronger, and the sleepers remembered more of a list of word pairs the next morning.
Later work repeated the approach, including a 2017 study in older adults that found stronger slow waves and better recall in those whose waves responded most. Every one of these studies used the same ingredients: EEG, a computer listening to the brain, and sounds lasting a fraction of a second, switched on and off in step with it.
A speaker playing pink noise all night does none of that. The studies are real and interesting, but they are evidence for timed bursts, not for steady pink noise.
What is known about steady noise
For steady noise, the kind a sound app or machine plays, the picture is thinner. A 2021 systematic review in Sleep Medicine Reviews collected studies of continuous noise for sleep and rated the evidence as very low certainty. Some found benefits, some found none, and many were small or poorly controlled.
So pink noise has not been shown to beat other sounds in ordinary use. Its real advantage is simpler: it is less sharp than white noise, which makes it easier to leave on.
Pink noise benefits: claims and evidence
The benefits listed for pink noise mix what labs found with what they did not test:
| Claim | What research shows |
|---|---|
| Deeper sleep | Timed bursts in labs strengthened slow brain waves. Not shown for steady pink noise from a speaker. |
| Better memory | Small lab studies with timed bursts found better overnight recall of word pairs. Not shown for steady noise. |
| Falling asleep faster | Not established. Evidence for steady noise in general is very low certainty. |
| Covering other noise | True of any steady sound: a constant background makes sudden noises stand out less. Pink noise is not special here. |
White noise vs pink noise for sleep
Between 2 and 12 kHz, Velvet noise stays about level, close to level, while White static rises 1.6 dB per octave. White noise has proportionally more energy at the top, which you hear as hiss. Pink noise keeps the balance even, so no part of the sound pushes forward.
Neither has been shown to work better. White noise has more energy where speech sits, so it covers voices a little more at the same volume; pink noise is gentler to listen to. If you are unsure, start with pink.
Band by band, in numbers
| Band | Velvet noise | White static | Difference |
|---|---|---|---|
| 2 kHz | −8.6 dB | −7.8 dB | +0.8 dB |
| 2.5 kHz | −8.8 dB | −7.2 dB | +1.6 dB |
| 3 kHz | −8.9 dB | −6.6 dB | +2.3 dB |
| 4 kHz | −8.8 dB | −5.7 dB | +3.1 dB |
| 5 kHz | −8.6 dB | −4.8 dB | +3.8 dB |
| 6 kHz | −8.4 dB | −4.2 dB | +4.2 dB |
| 8 kHz | −8.4 dB | −3.5 dB | +4.9 dB |
| 10 kHz | −9.0 dB | −3.8 dB | +5.2 dB |
| 12 kHz | −10.0 dB | −4.6 dB | +5.4 dB |
Pink noise vs brown noise
Brown noise goes further in the same direction: its power falls faster as pitch rises, so it is deeper still. In Hush, Deep brown falls 3.4 dB per octave between 2 and 12 kHz. If pink noise sounds too bright, brown is the next step down; is brown noise good for sleep? covers it.
How to try pink noise
A fair trial takes a few nights:
- Keep it quiet, just enough to soften the room.
- Place the speaker across the room, not beside your head.
- Decide how it ends: a sleep timer with a fade, or play until morning if you wake when sound stops.
- Give it three or four nights before judging it.
- If it feels too bright, try brown noise; if too dull, try white.
