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What is Brown Noise?
Brown noise — sometimes called Brownian noise or red noise — is a type of sound signal where the energy is concentrated in the lower frequencies. Unlike white noise, which distributes energy equally across all audible frequencies and can sound harsh or hissing, brown noise produces a deep, rich rumble that many people describe as resembling a strong waterfall, distant thunder, or heavy wind blowing through a forest.
The name comes from Robert Brown, the botanist who first described Brownian motion — the random movement of particles suspended in a fluid. Brown noise follows this same mathematical pattern: each successive sample is a random step from the previous one, producing a signal whose power density decreases by 6 decibels per octave as frequency increases. In practical terms, this means you hear far more bass and low-mid energy than treble, which is why it sounds so warm and enveloping.
On the sound color spectrum, brown noise sits below pink noise and far below white noise. Where white noise sounds like static and pink noise sounds like a steady rainfall, brown noise sounds like the roar of a river or the low hum of an engine. This deeper profile makes it particularly effective at masking low-frequency environmental disturbances — traffic rumble, a neighbor's bass, an air conditioner, a washing machine two rooms away — because its dominant low frequencies overlap with the most common sources of household noise. That overlap is also its limit: a sound can only mask what it shares a frequency region with, so the same profile that covers a passing truck so well does very little for anything high-pitched.
Benefits of Brown Noise for Sleep
Falling asleep in a noisy world is hard. Brown noise creates a consistent acoustic blanket that helps your brain stop scanning for changes in the environment — the sudden car horn, the neighbor's dog, the refrigerator clicking on. By providing a steady, predictable sound floor, brown noise allows your nervous system to relax and transition into the deeper stages of sleep more quickly.
Research into sound-based sleep aids has grown significantly, and while individual responses vary, many users report falling asleep faster, waking up less during the night, and feeling more rested in the morning when using low-frequency sound environments. The deep quality of brown noise is particularly relevant here, because it avoids the high-frequency energy that some people find stimulating or irritating in white noise.
Beyond sleep, brown noise has gained popularity among people with ADHD as a focus aid. The theory is that the steady auditory input provides just enough stimulation to prevent the brain from seeking distractions, without being interesting enough to become a distraction itself. Students, remote workers, and creative professionals frequently report improved concentration and longer periods of uninterrupted work when using brown noise as a background sound. The measured evidence is narrower than the trend implies: a 2024 systematic review and meta-analysis in the Journal of the American Academy of Child and Adolescent Psychiatry pooled 13 randomised trials in children and adolescents and found a small benefit of white and pink noise on laboratory attention tasks for young people with ADHD or elevated attention problems, a small negative effect for those without ADHD, and no trials of brown noise at all. Note the population: the review looked at youth, so it says nothing directly about the adults who make up most of the brown-noise-for-focus trend.
Tinnitus is the other reason people arrive here, and it deserves a more careful answer than it usually gets — including from pages like this one. Masking is frequency-specific: a masker raises your detection threshold for sounds close to it in frequency and does very little for sounds far away from it. Brown noise concentrates its energy at the bottom of the spectrum, shedding about 20 decibels by 1 kHz relative to 100 Hz and roughly 34 by 5 kHz, leaving very little in the range where tinnitus usually sits. Tinnitus, meanwhile, is most often described by the people who have it as a high tone — a ring, a whistle, a hiss, cicadas, a kettle. Against a percept like that, brown noise is simply the wrong color, and turning it up does not fix a pitch mismatch; it only adds sound exposure. White or pink noise will usually mask more at a lower volume.
Brown noise does earn its place in two situations: a low-pitched percept — a hum, a drone, a rumble — and comfort, because a sound you can actually leave running for eight hours is worth more than a theoretically better masker you switch off after twenty minutes. What it is not is a treatment. The 2014 American Academy of Otolaryngology–Head and Neck Surgery clinical practice guideline on tinnitus (Tunkel and colleagues) lists sound therapy as an option — its weakest tier — while making a full recommendation for cognitive behavioral therapy, and a hearing aid evaluation where there is documented hearing loss. Masking makes tinnitus less audible while the sound plays. That is a comfort measure, and it is worth exactly what it is worth. Our full guide to brown noise for tinnitus covers the pitch problem in detail, what the 2018 Cochrane review of sound therapy did and did not find, how to set the level safely, and which symptoms belong in a clinic rather than in an app.
Brown Noise vs. White Noise vs. Pink Noise
Sound colors are classified by how their energy is distributed across frequencies. Understanding the differences helps you choose the right type of noise for your specific needs — whether that is deep sleep, focused work, or masking tinnitus.
White Noise
White noise contains equal power across all audible frequencies, from the lowest bass to the highest treble. It sounds like TV static, a hissing radiator, or an untuned radio. Because it includes a lot of high-frequency energy, some people find it harsh or fatiguing over long periods. White noise is effective for masking sudden, sharp sounds like door slams or car horns, and it remains one of the most widely studied sound types for sleep. That research is far less conclusive than its popularity suggests. The most relevant synthesis — Riedy, Smith, Rocha and Basner, Noise as a sleep aid: A systematic review (Sleep Medicine Reviews, 2021) — assessed 38 articles on continuous white noise and similar broadband noise. Findings ranged from continuous noise improving sleep to continuous noise disrupting it, and under the GRADE criteria the authors rated the quality of evidence for continuous noise improving sleep as very low, a conclusion they noted contradicts its widespread use.
Pink Noise
Pink noise reduces power by 3 decibels per octave as frequency increases, giving it more bass presence than white noise while still retaining some higher-frequency detail. It sounds like steady rain, wind through leaves, or a gentle stream. Pink noise has been studied for its potential to enhance deep sleep — a 2017 study in Frontiers in Human Neuroscience found that acoustic stimulation timed to slow-wave sleep oscillations could improve memory consolidation in older adults. Pink noise is often described as more balanced and natural-sounding than white noise.
Brown Noise
Brown noise drops power by 6 decibels per octave, concentrating almost all its energy in the low and mid-low frequencies. The result is a deep, rumbling sound similar to a strong waterfall, distant thunder, or the low drone of an airplane cabin. This heavy bass profile makes brown noise the most effective of the three at masking low-frequency environmental disturbances — things like traffic rumble, HVAC systems, and the bass from a neighbor's music. For sleep, many users prefer brown noise precisely because it lacks the high-frequency edge that can make white noise feel intrusive. Masking, though, is a physical relationship rather than a clinical claim: a sound can only mask a disturbance whose frequency range it overlaps, and brown noise puts most of its energy in the same low bands where traffic, HVAC plant and machinery put theirs. That is why brown noise covers a passing truck more convincingly than a hiss does — and it is not, on its own, evidence that brown noise improves sleep. No controlled sleep trial has tested brown noise by itself. The gap is wide enough that the 2024 meta-analysis in the Journal of the American Academy of Child and Adolescent Psychiatry, which set out to pool randomised trials of white, pink and brown noise on attention tasks, reported that no studies of brown noise were identified at all. If brown noise helps you sleep, that is a real result for you; it is not yet a result the published literature can confirm.
Which Should You Choose?
If you are sensitive to high-pitched sounds or find white noise irritating, brown noise is almost certainly the better option for sleep. If you want something in between — softer than white noise but not as bass-heavy as brown — pink noise is a good middle ground. Many people experiment with all three before settling on their preferred type. Our app includes brown, white, pink, blue, and green noise so you can find the perfect sound for your ears.
Frequently Asked Questions
Is brown noise safe for babies?
Brown noise is generally considered safe for babies when played at a reasonable volume. Commonly cited guidance suggests keeping the volume below roughly 50 decibels — about the level of a quiet conversation — and placing any speaker at least a few feet from the crib, though recommendations vary. Many parents find that the deep, consistent tone of brown noise helps soothe infants to sleep more effectively than white noise. This is not medical advice — always consult your pediatrician before using sound therapy with an infant, or if you have concerns about your baby's hearing or sleep habits.
Does brown noise help with tinnitus?
Not in the way it is usually claimed. Masking only works where the masker and the tinnitus share a frequency region, and brown noise puts almost all of its energy low down, with very little left above about 5 kHz. Tinnitus is most often described as a high tone — a ring, a whistle, a hiss — so against a percept like that brown noise is the wrong color, and raising the volume does not fix a pitch mismatch. White or pink noise will usually mask more at a lower level. Brown noise is the better match for a low hum, drone or rumble, and some people choose it regardless because it is comfortable enough to leave running all night. Either way it is a comfort measure while the sound plays, not a treatment: the 2014 American Academy of Otolaryngology–Head and Neck Surgery guideline lists sound therapy as an option, its weakest tier, and reserves a full recommendation for cognitive behavioral therapy. Our full guide to brown noise for tinnitus explains how to choose a color and set the level.
What is the difference between brown noise and white noise?
White noise contains equal energy across all frequencies, producing a bright, hissing sound similar to TV static. Brown noise has significantly more energy in the lower frequencies, creating a deep, rumbling tone similar to a waterfall, strong wind, or distant thunder. Most people find brown noise warmer, less fatiguing, and more soothing for sleep compared to the sharper quality of white noise.
Why should I download the app instead of using the website?
The web player is great for a quick session, but the app offers unlimited playback with no session limits, offline mode so you don't need an internet connection, a built-in sleep timer that automatically stops playback, background play while using other apps, and the ability to mix brown noise with rain, thunder, and other nature sounds for a personalized soundscape.
Medical Disclaimer
The information on this website is provided for general educational purposes only and is not medical advice. Brown noise and other sound therapies are not a diagnosis, treatment, or cure for any medical condition, including insomnia, tinnitus, ADHD, or any hearing or sleep disorder.
Always consult a qualified healthcare professional — such as your doctor, an audiologist, or your child's pediatrician — before relying on sound therapy for a health concern, and especially before using it with infants or anyone with existing hearing sensitivity. Never disregard or delay professional medical advice because of something you have read here.
Individual results vary. Any research referenced on this page describes general findings and does not guarantee a particular outcome for you. If you experience discomfort, ear pain, worsening symptoms, or persistent sleep problems, stop use and seek medical guidance.
Brown Noise for Sleep: Brw is coming to iPhone and iPad. It is not out yet, so there is nothing to download — but the player at the top of this page is free and needs no app, so you can start listening now.