Brown noise vs white noise (and pink and green): which to use

What is the difference between brown noise and white noise?

The difference between brown noise and white noise is where the energy sits. White noise spreads the same energy across every frequency, so the high end stands out and it sounds like a hiss, a fan or TV static. Brown noise loses 6 dB of energy for every octave you go up (an octave is a doubling of pitch), so the low end dominates and it sounds like a deep, soft rumble.

The colours are borrowed from light. White light contains every colour, so noise with every frequency at equal strength is called white. Brown noise is not named after the colour at all: it comes from Brownian motion, the random drifting of tiny particles studied by the botanist Robert Brown. Some people call it red noise.

What do pink, green and orange noise mean?

Pink noise sits between white and brown, and green and orange are looser names. Here is how they compare:

Colour	How the energy is spread	Sounds like
White	Equal at every frequency	Hiss, fan, radio static
Pink	Falls 3 dB per octave	Steady rain, wind in trees
Brown	Falls 6 dB per octave	Low rumble, distant waterfall, strong surf
Green	Centred on the middle, around 500 Hz	Soft, “natural” whoosh
Orange	No standard definition	Varies by source

White, pink and brown have exact mathematical definitions. Green and orange do not. You will hear them described in different ways by different apps and machines, and there is no research on either one for sleep.

Is brown noise or white noise better for sleep?

Neither has been proven better, so the honest answer is the one you find easier to ignore. Many people prefer brown noise for sleep because white noise can sound sharp at night, and the ear is more sensitive to those higher frequencies.

Noise helps in one main way: it masks. A sudden sound, like a car door or a cough through the wall, wakes you because it stands out against silence. Steady noise lowers that contrast. That works with any colour, as long as it covers the sounds that bother you. Deep traffic rumble is masked better by brown noise; higher sounds like voices are masked better by white or pink.

The research is less clear than the marketing. A 2021 systematic review of noise as a sleep aid rated the evidence that continuous noise improves sleep as very low quality. Results in the studies it covered ranged from better sleep to worse sleep, and the authors warned that noise may also harm sleep and hearing. So treat noise as a comfort tool, not a sleep treatment.

Does pink noise improve deep sleep?

Only in a special lab setup so far. In a 2013 study in Neuron, short sounds timed to each slow wave of deep sleep made those waves stronger and improved memory the next day. A 2017 study timed short pulses of pink noise the same way in 13 older adults and found stronger slow waves and better word recall the next morning.

The key word is timed. The sound was switched on and off in step with the sleeper’s brain waves, measured live with EEG sensors. A steady pink noise track playing all night is not the same thing, and those studies do not show that it boosts deep sleep. If you want sound that targets slow sleep rhythms, a delta binaural beat is the closer match, and we explain the numbers in best frequency for sleep.

Which noise colour is best for focus?

There is no proven best colour for focus, but brown noise is the most popular choice. Its deep sound blocks chatter in an open office without the brightness of white noise, which some people find tiring after an hour or two. Studies on noise and attention are few and small, and results differ from person to person. People with ADHD often report that brown noise helps; we look at what the research says in brown noise for ADHD.

A practical approach for a working session:

• Start with brown noise at a low volume.
• If it feels muddy or sleepy, switch to pink.
• If you need to block voices, try white or pink.
• Give each one at least 20 minutes before you decide.

Is it safe to sleep with noise all night?

For most adults, yes, as long as the volume is low. Keep it well below the level of normal conversation, which is about 60 dB, and place any speaker away from your head. If you only need noise to fall asleep, a timer that fades the sound out once you are asleep gives your ears a quiet rest for the rest of the night.

In Shimmr, you can layer white, pink, brown, green or orange noise under any session in the mixer, for example under the Awake → Asleep Shift, and let the sleep timer fade everything out. It works offline and keeps playing with the screen off.

If you have ringing in your ears (tinnitus) or trouble sleeping most nights for weeks, talk to a doctor. Noise can make a room easier to sleep in, but it does not treat a sleep problem.