Brown noise

What is brown noise?

Brown noise isn't deeper sleep. It's deeper sound — more energy in the low frequencies, less hiss. Technically its power drops by about 6 dB per octave as you go up the spectrum, which stacks nearly all the loudness below a few hundred hertz. Where white noise is an even hiss, brown noise is a rumble: surf on a long beach, a jet cabin at cruise, thunder that never quite arrives.

The name has nothing to do with the color. It's from Robert Brown, the botanist behind Brownian motion — the random walk of a particle knocked around by molecules. Generate audio the same way, letting each sample drift a small random step from the last, and brown noise is what comes out. That's literally what this page does: the generator above runs a leaky integrator over white noise, a random walk with a slow leak so it never wanders off.

Why lower feels warmer

Your ear is least sensitive at the frequency extremes and most sensitive in the 2,000 to 5,000 Hz band — the region of speech consonants, alarms, and a baby's cry. White noise parks a lot of energy exactly there, which is why many people describe it as harsh or "staticky." Brown noise nearly vacates that band. What's left occupies the register of large, slow, far-away things — and a lifetime of experience has taught your threat system that large, slow, far-away sounds are rarely urgent.

Masking still works, with one caveat: with little high-frequency energy, brown noise is slightly worse at covering high-pitched interruptions — a beep, a bird at 5 a.m. If your noise problem is high-pitched, white or pink covers it better. If your problem is a rumbling street or a snoring human, brown meets it on its own turf.

The evidence, honestly

No study shows brown noise produces measurably better sleep than white or pink — the comparative literature barely exists. What research there is covers continuous noise in general: a 2021 systematic review of 38 studies found low-quality but broadly positive evidence for falling asleep in noisy rooms, and no established benefit in quiet ones.

Then there's the focus claim. Around 2022, brown noise had a viral moment as an "ADHD hack," and some people with ADHD do report it quiets mental chatter. Take the reports seriously and the mechanism claims lightly: there's no published evidence of a specific neurological effect of brown noise on attention. The boring explanation — steady noise masks distraction and gives an under-stimulated auditory system something constant to rest on — accounts for most of it. If it helps you, it helps you; you don't need the viral theory to justify the habit.

How to use it tonight

• Volume: just above the sound you're masking, around 50 dB. Start at 30% here. Low-heavy doesn't mean high volume is safe — loudness is loudness.
• Placement: speaker across the room. Low frequencies fill a room well; you don't need it near your head.
• Timer: use the 30- or 60-minute timer if you only need help falling asleep — it ramps down over ten seconds rather than cutting out.
• Small speakers: phone speakers can't reproduce much below ~500 Hz, so brown noise on a phone sounds thin. A modest bluetooth speaker restores the body of it.

Where it fits in a wind-down

A noise bed settles the room; it doesn't decide what your attention does inside it. The pairing that works in practice: put brown noise under the room, then give the last ten minutes before sleep to something chosen on purpose — a page of a book, slow breathing, or a short daily audio like the AYA Method, where the voice you fall asleep to is your own future self rather than the day's leftovers. The rumble handles the street. The voice handles the story.

Machine, app, or this page?

Three honest ways to run brown noise all night, with the trade-offs stated plainly. A dedicated sound machine ($20–60) is the most reliable: it survives phone calls, needs no screen, and the better ones generate noise rather than looping a recording — listen at the store for a repeating seam, which your half-asleep brain will eventually find. A phone app is the most convenient and the most compromised: notifications interrupt, batteries drain, and the phone ends up on your nightstand, which costs many people more sleep than the noise saves. A browser generator like this one is the free middle path — genuinely synthesized, gapless, no install — best run on a laptop, tablet, or spare device across the room, since mobile browsers often stop audio when the screen locks.

Whichever you choose, the settings that matter are the same two: volume around conversation level, and source across the room. Everything else — brand, "precision engineered" marketing, the number of moon-phase presets — is upholstery.

Brown vs. the other colors

Thirty seconds of each tells you more than any table. Play them side by side — white, pink, brown — and keep whichever one your breathing slows down to.