We make Drop, a sleep and calm sounds app that plays white, pink and brown noise. It is one option among several: the iPhone's built-in sounds and the other apps listed below also do it. We say where Drop fits at the end.
The difference in one table
| White noise | Pink noise | Brown noise | |
|---|---|---|---|
| What it is | Equal energy at every frequency | Energy falls as pitch rises (equal per octave) | Energy falls faster still; mostly low frequencies |
| Sounds like | Static, a hiss, a TV between channels | Steady rain | A waterfall, a deep rumble |
| Sleep | Evidence for continuous noise of any colour is very low quality (Riedy 2021). One small study found more stable sleep with pink noise (Zhou 2012). | ||
| Focus | Small benefit in people with ADHD; slightly worse performance in people without it (Nigg 2024) | No studies found (Nigg 2024) | |
| Baby | Volume and distance matter more than colour: all 14 machines tested at full volume were above the hospital nursery limit at 30 cm (Hugh 2014) | ||
The “sounds like” row follows the 2024 meta-analysis by Nigg and colleagues, which describes white noise as sounding “like static” and pink or brown noise as having “more power in the lower frequencies” and sounding “like rain or a waterfall”.
For sleep
The most complete look at the question is a systematic review by Riedy, Smith, Rocha and Basner at the University of Pennsylvania (Sleep Medicine Reviews, 2021). It covered 38 studies of continuous white or similar broadband noise and sleep. Results ranged from noise improving sleep to noise disrupting it, and under the GRADE criteria the quality of evidence that continuous noise improves sleep was very low. The authors warn it “may also negatively affect sleep and hearing”.
Pink noise has some extra interest. In a small study (Zhou et al., Journal of Theoretical Biology, 2012), 40 people slept a night with steady pink noise and a night in quiet, and the noise nights showed a higher share of stable sleep. A different line of research plays short pulses of pink noise timed to deep-sleep brain waves: in 13 older adults (Papalambros et al., 2017) it increased slow-wave activity and next-day word recall. That needs EEG equipment in a lab; a pink noise track on your phone does not do it.
We found no controlled study of brown noise for sleep. Brown noise is popular on social media; the research has not caught up.
In practice: if a steady sound masks the traffic or the neighbours, use the colour you find least irritating, at the lowest volume that works, and use a timer.
For focus
A 2024 meta-analysis (Nigg et al., Journal of the American Academy of Child and Adolescent Psychiatry) pooled 13 studies with 335 children and young adults with ADHD or ADHD symptoms. White and pink noise gave a small improvement on lab attention tasks. In people without ADHD (11 studies, 335 people), they made performance slightly worse. The authors found no studies of brown noise at all.
For a baby
Researchers in Toronto measured 14 infant sleep machines at maximum volume (Hugh et al., Pediatrics, 2014). At 30 cm every one was louder than 50 dBA, the recommended limit for hospital nurseries, and three exceeded 85 dBA, the level that over 8 hours breaks adult workplace limits. The colour of the noise did not come into it. Put the phone or machine well away from the cot, keep the volume low, and use a timer; ask your paediatrician if you are unsure.
Step by step
- Try the noise built into your iPhone. Settings, Accessibility, Audio & Visual, Background Sounds, turn it on (Apple). The sounds include Balanced Noise, Bright Noise and Dark Noise, plus Ocean, Rain and Stream (AppleInsider). Apple does not say which colour of noise each one is.
- Shape it with the Equalizer. On iOS 26 or later, Background Sounds has an Equalizer: tap it and drag across the grid to cut the high or low frequencies until it sounds right to you.
- Set a timer. In the same screen, Stop Sound with a Timer. You can also start and stop Background Sounds from Control Center.
- Keep the volume low. Use the lowest level that covers the noise you want to mask. For a baby, put the phone well away from the cot.
- If you want true brown or pink noise, use an app that names it. White Noise Lite, myNoise, Rain Rain, Endel and Drop list it on the App Store (details below).
- If noise is not for you, try nature sounds or slow breathing. Rain or ocean is easier on the ear for many people. Drop has rain, ocean and other nature sounds and a guided breathing timer.
Apps that play pink or brown noise (App Store, 23 October 2026)
- White Noise Lite (TMSoft, free with ads, 8.7.3, 4.82 from about 278,000 ratings): its sound list includes Brown Noise, Pink Noise, White Noise, Blue Noise and Violet Noise, with a mixer and fading timer.
- myNoise (free, 3.21.77): its “White Noise & Co” soundscape covers white, brown, green, grey and pink noise, each with its own sliders.
- Rain Rain Sleep Sounds (free, 6.9.10): lists Pink Noise among 50+ sounds, with a free mixer and fade-out timer.
- Endel (free, Premium for Colored Noise): “choose one of 9 colors of noise”.
- Dark Noise (free, 3.6.1): 50+ ambient sounds, custom mixes and a fade-out timer.
- Drop (free, 2.10, 24 October 2026): White Noise free; Pink Noise, Brown Noise and Deep Brown Noise with Drop Pro, among 53 sounds. One sound at a time, no mixer or equaliser, sleep timer with fade-out.
Where Drop fits
Drop's App Store listing (version 2.10, 24 October 2026) describes nature sounds (gentle rain, crystal dewdrops, crackling campfire, mystical forest, ocean waves), guided breathing sessions of 2, 5, 10 and 20 minutes, widgets, a plant that grows as you practise, offline use and no ads. Version 2.10 has 53 sounds, 9 of them free. White noise is free; pink, brown and deep brown noise come with Drop Pro. They are fixed looped tracks, one at a time, so if you want to shape the colour or layer it with rain, myNoise or White Noise Lite do more. If you tried brown or pink noise and found it grating, rain or ocean with a few minutes of slow breathing is the other route it offers. More on Drop's page, and the step by step in how to use white noise to fall asleep on iPhone.
Sources
- Riedy SM et al. Noise as a sleep aid: a systematic review. Sleep Med Rev 2021;55:101385.
- Hugh SC et al. Infant sleep machines and hazardous sound pressure levels. Pediatrics 2014;133(4):677-81.
- Zhou J et al. Pink noise: effect on complexity synchronization of brain activity and sleep consolidation. J Theor Biol 2012;306:68-72.
- Papalambros NA et al. Acoustic enhancement of sleep slow oscillations and concomitant memory improvement in older adults. Front Hum Neurosci 2017;11:109.
- Nigg JT et al. Do white noise or pink noise help with task performance in youth with ADHD? J Am Acad Child Adolesc Psychiatry 2024;63(8):778-788.
- Apple, Use Background Sounds to help with sleep, focus, and more (109346) and Play background sounds on iPhone, read 23 October 2026.
- App Store listings of the apps above, US store, read 23 October 2026.
Questions people ask
Is brown noise better than white noise for sleep?
There is no study showing that. A 2021 review of 38 studies rated the evidence that any continuous noise improves sleep as very low quality, and we found no controlled study of brown noise and sleep. Use whichever you find least irritating, quietly.
Is pink noise good for sleep?
One small 2012 study found more stable sleep with steady pink noise. Lab studies that play pink noise pulses timed to deep-sleep brain waves improved memory in older adults, but that is not the same as a pink noise track.
Which noise is best for focus or ADHD?
A 2024 meta-analysis found a small benefit of white and pink noise for people with ADHD and a small negative effect for people without it. It found no studies of brown noise.
Is white noise safe for a baby?
The concern is volume. A 2014 study found all 14 infant sleep machines exceeded 50 dBA at 30 cm at full volume. Keep the device far from the cot, at low volume, with a timer, and ask your paediatrician.
Can I play brown noise on iPhone without an app?
iPhone's Background Sounds (Settings, Accessibility, Audio & Visual) has Balanced, Bright and Dark Noise. Apple does not label them by colour.
Does Drop have brown or pink noise?
Yes, since version 2.10 (24 October 2026). White noise is free; pink, brown and deep brown noise come with Drop Pro. For free coloured noise, use the iPhone's Background Sounds or White Noise Lite.