Brown vs pink vs white noise: the difference, and which is best for sleep
- White noise: equal energy at every frequency. Sounds like a bright hiss or radio static.
- Pink noise: energy falls about 3 dB per octave. Sounds like steady rain or wind.
- Brown noise: energy falls about 6 dB per octave. Sounds like a deep rumble, strong surf or a waterfall.
- For sleep: no color is proven best for everyone. Pick the one you find most comfortable at a low volume.
What "noise color" means
Noise colors describe how a sound's energy is spread across low and high pitches. The names borrow from light: white light contains all colors equally, and white noise contains all audible frequencies equally. The other colors tilt that balance toward the low end.
| White noise | Pink noise | Brown noise | |
|---|---|---|---|
| Energy | Equal at every frequency | Equal in every octave; falls ~3 dB per octave | Falls ~6 dB per octave |
| Sounds like | Static, hiss, a fan on high | Steady rain, wind, a fan on medium | Deep rumble, surf, a fan on low |
| Feels | Bright, sharp | Balanced, soft | Warm, heavy |
| Often chosen for | Masking voices and high-pitched sounds | All-round background sound | People who find hiss irritating |
Brown noise is also called Brownian or red noise. The name comes from Brownian motion, not the color.
Where does a box fan fit?
A box fan is not a pure noise color. Its sound comes from air turbulence around the blades, plus a little motor hum. Most of that energy sits in the low and middle frequencies, so a fan usually sounds closer to pink or brown noise than to the hiss of pure white noise. Turn the fan up and the sound gets brighter; turn it down and it gets deeper.
That is exactly how Box Fan Sleep works: one-tap Brown, Pink and White presets, and a slider that moves through 7 tones, from Deep Brown and Warm Brown, through Soft and Balanced Pink, to Light, Bright and Crisp White.
What the research says about noise and sleep
Steady sound helps by masking: sudden noises stand out less against a constant background. Whether that actually improves sleep is less clear.
- New in 2026: a University of Pennsylvania sleep-lab trial in SLEEP found that continuous pink noise at 40 to 50 dBA reduced REM sleep by up to about 19 minutes per night in adults who didn't normally sleep with sound, and that foam earplugs protected sleep from traffic noise better than pink noise. Full summary.
- A 2021 systematic review of 38 studies, published in Sleep Medicine Reviews, rated the evidence that continuous noise improves sleep as very low quality. The authors also cautioned that continuous noise may affect sleep and hearing.
- A 2022 systematic review in the Journal of Clinical Sleep Medicine looked at 34 studies. Pink noise studies reported positive results more often than white noise studies, but the authors found no strong evidence overall and no reported harms from short-term use.
- Lab studies that play very short pulses of pink noise timed to deep-sleep brain waves (for example, a 2024 study in older adults in Frontiers in Sleep) have boosted deep-sleep activity. That technique uses EEG equipment and is different from playing a sound all night.
The honest takeaway: a fan sound is a comfort tool. If it helps you, use it at a sensible volume. If it doesn't, a different color may suit you better, or you may sleep best in quiet.
How to choose
- Start with pink. It is the middle ground and the most common choice.
- If it sounds hissy or harsh, move toward brown.
- If voices or TV still get through, move toward white, which covers higher pitches better.
- Give each one a few nights. First impressions change once the sound fades into the background.
- Use the lowest volume that masks what bothers you, and keep the speaker a few feet from your head.
- Use a sleep timer. Masking matters most while you fall asleep; letting the sound fade afterwards avoids all-night exposure.
Try all three in one app
Box Fan Sleep is free on iPhone and iPad. Open the app, tap Brown, Pink or White, then fine-tune with the slider. With the one-time $2.99 Pro upgrade you can layer rain, thunder, crickets or ocean on top.
Frequently asked questions
Is brown noise better than white noise for sleep?
There is no proven winner. Brown noise has more deep, low-frequency energy and many people find it less harsh, while white noise sounds brighter and hissier. Research reviews have not found strong evidence that any noise color improves sleep for everyone, so the best choice is the one you find most comfortable at a low volume.
What is the difference between pink noise and white noise?
White noise has equal energy at every frequency, which our ears hear as a bright hiss. Pink noise has equal energy in every octave, so its power falls as pitch rises (about 3 dB per octave). It sounds softer and fuller, like steady rain.
What color noise is a box fan?
A box fan makes broadband noise that is not a pure noise color. Most fans sound closer to pink or brown noise than to pure white noise, because more of their energy sits in the low and middle frequencies. Higher fan speeds sound brighter.
Is it safe to sleep with white noise all night?
Be cautious about all-night use. A 2026 University of Pennsylvania sleep-lab trial found that continuous pink noise at 40 to 50 dBA reduced REM sleep in adults who did not normally sleep with sound. Keep the volume low, keep the source a few feet from your head, and use a sleep timer so the sound fades out after you fall asleep.
Can I try brown, pink and white noise in one app?
Yes. Box Fan Sleep has one-tap Brown, Pink and White presets and a slider with 7 tones in between, all free on iPhone and iPad.
Sources
- Riedy SM, Smith MG, Rocha S, Basner M. Noise as a sleep aid: A systematic review. Sleep Medicine Reviews. 2021;55:101385. doi:10.1016/j.smrv.2020.101385
- Basner M, et al. Efficacy of pink noise and earplugs as countermeasures against environmental noise-induced sleep disruption. SLEEP. 2026. doi:10.1093/sleep/zsag001
- Capezuti E, et al. Systematic review: auditory stimulation and sleep. J Clin Sleep Med. 2022;18(6):1697–1709. doi:10.5664/jcsm.9860
- Hugh SC et al. Infant sleep machines and hazardous sound pressure levels. Pediatrics. 2014.
Hear the difference tonight
Brown, pink and white fan sound, free on iPhone and iPad. No subscription.