Brown Noise

What Is Brown Noise, and What Does It Sound Like?

Brown noise is deep and steady. Some call it Brownian noise, others red noise. It carries more low tone and far less hiss than white noise. What does it sound like? Picture a weir in full flow. Or rain drumming on a conservatory roof. Or the steady drone of a long-haul flight. The colour brown has nothing to do with the name. It comes from Robert Brown, a botanist who studied the way pollen grains jitter about in water. The same maths behind that jitter also produces this sound. That deep rumble is why so many people reach for brown noise at bedtime or at their desk.

Press Play and Free Brown Noise Starts Straight Away.

No ads, no sign-up, nothing to install: the sound starts the moment you press play. Treat this page as a free brown noise generator and sound machine, running right there in your browser. The loop has no gap, no click and no fade. Set it going at bedtime and it'll still be rumbling away 10 hours later when your alarm goes off. It does the same job for revision, coding, or any long stretch of deep work.

Here's why people rate this player:

• No ads, ever. No ads at 3am, no banners popping up. Think of it as a radio station that only ever plays brown noise.
• Barely any data. It streams all night without making much of a dent in your data.
• One tap. Press play at night, press pause in the morning. That's the whole trick.
• Sleep timer. Choose 15 minutes, 12 hours, or anything in between, and the rumble tapers off on its own. You'll never have to wake up just to switch it off.
• Black Screen mode. The screen goes dark while the brown noise carries on playing. No glow lighting up the room, and it's kinder to your battery too.

Brown Noise vs White Noise: Which One Helps You Sleep?

Both sounds can mask whatever it is that wakes you, but they don't sound remotely alike. White noise has equal power across every pitch, which is why plenty of people find it sharp and hissy. Brown noise fades as the pitch climbs, leaving a warm, low wash of sound with next to no hiss.

That low end is really the whole argument for it. Plenty of the sounds that wake you sit down low too: traffic, a snoring partner, the upstairs neighbours crossing the landing. Brown noise keeps its own energy in that same low register, which is the physics case for it as a masker; no sleep study has yet pitted brown noise against white noise head-to-head. Your brain stops checking every thud, and off you drift.

"The best sound for sleep is not silence. It is a sound so steady your brain stops listening."

What Does the Research Actually Say About Brown Noise and Sleep?

Less than you'd think from browsing the internet. The one job it's solidly good at is covering other sounds. In a lab that played recorded hospital noise to five sleepers, arousals rose from about 13 an hour to 48; among the four who then slept a night with a steady noise layered over the top, the rate dropped back to about 16 (Stanchina 2005). That trial used white noise, not brown; brown noise has close to no sleep trials of its own.

Beyond masking, the evidence thins out fast. A review of 38 studies on steady noise as a sleep aid rated the certainty of the whole body of evidence as "very low" (Riedy 2021). The largest trial we know of split 495 working adults four ways; the 128 who spent four weeks using sleep sounds ended up no better off than a matched comparison group (Vazzaz 2026). Which leaves us here: brown noise covers the sounds you can't do anything about, and it gives a racing mind something dull to settle on. It won't treat insomnia. If most nights are a battle, it's worth seeing a doctor.

How to Use Brown Noise for Sleep

The rumble itself is the easy bit. Getting the volume right, timing it well, and knowing what it can and can't cover is what makes it work, night after night.

Should You Leave Brown Noise on All Night, or Put It on a Timer?

Match the approach to your problem. If the hard part is nodding off, a 30-to-90-minute timer does the job; the sound fades once you're already gone. If any change in the room stirs you awake, or the traffic starts building before sunrise, leave it purring away quietly until morning. Tap Black Screen and the page fades to black while the sound plays on.

A recent study makes the case for choosing deliberately rather than out of habit. Over seven nights with 25 adults, pink noise layered on top of outside noise cut into REM sleep and left overall sleep structure worse off, while plain earplugs handled the same noise better (Basner 2026). It's a modest study, but it's a fair argument for the timer whenever you don't genuinely need the sound running until morning.

How Loud Should Brown Noise Be at Night?

Quieter than feels natural. A decent test: if you'd need to raise your voice to hold a normal conversation over it, it's too loud. Loud steady noise costs you more than it gives back. In one daytime office study, 45 dB of white noise sharpened attention, while 65 dB brought more typing errors and, against the quieter setting, slower work and higher stress readings (Awada 2022); nobody has repeated that test overnight. And when the street outside is loud enough to carry through a closed window, deal with that first using earplugs, then let brown noise smooth out whatever still gets through.

Does Brown Noise Cover Up Snoring and Traffic?

Traffic, yes, most of the time. What pulls you out of sleep is the size of the jump from quiet to loud, not the loud sound by itself. In the sleep-lab data, people stirred at roughly the same jump, about 17.7 versus 17.5 dB, whether or not a steady noise had been added, and the added noise cut their arousals by two-thirds simply by raising the floor (Stanchina 2005). In home recordings pooled from two field studies, about 100 people and nearly 30,000 traffic, train and aircraft noise events, each extra 10 dB of indoor peak raised the odds of waking by roughly 35% (Basner and McGuire 2018). Traffic, footsteps, and gurgling pipework are all low sounds, and low is exactly where brown noise keeps its energy.

Snoring is the harder case. It's loud, it's irregular, and it's a matter of inches from your ear, so a masking sound would have to run at an uncomfortable volume to bridge that gap. No published study has tested a masking sound for a snorer's partner. What has been tested is treating the snorer: across ten couples, fixing one partner's breathing during sleep dropped the other partner's arousals from 21 an hour to 12 (Beninati 1999). Loud snoring with pauses, gasps, or daytime sleepiness is a matter for a doctor's appointment, not a volume dial.

Is It OK to Play Brown Noise Every Night?

Kept quiet, yes. When researchers reviewed 34 studies of white and pink noise for sleep, 1,103 people in total, none of the short-term trials reported any harm (Capezuti 2022). Nobody has followed brown-noise sleepers over years, so that question stays open. Babies are a separate matter, with much firmer limits on volume and distance; see our baby page.

Who Listens to Brown Noise?

Brown noise has fans well beyond the bedroom. Here's a look at who keeps it running:

• People with ADHD, and anyone chasing focus. Plenty of people with ADHD say brown noise quietens the buzz in their heads. The trials so far cover white and pink noise, not brown, and the small attention gains they found only turned up in the ADHD groups (Nigg 2024). It's also popular for revision, coding, and long stretches of writing.
• Light sleepers and night-shift workers. The deep rumble swallows up street noise and daytime clatter, which helps anyone sleeping at odd hours, or next to a snorer.
• People with ringing ears (tinnitus). Some people find the rumble easier to live with than the ringing. Keep your expectations modest here: a Cochrane review of eight trials (590 people) found that no trial had even tested sound devices against waiting or plain information, and rated what evidence it did find as low quality (Sereda 2018). If it helps you, keep it at the lowest level that gives relief, and get sudden or one-sided ringing checked by an audiologist.
• Travellers and hotel sleepers. An unfamiliar room is often too quiet. The same rumble you sleep to at home plays in any browser, on any phone, anywhere you've got a signal.

Is Brown Noise the Same Thing as a Fan?

Close, but not quite. A fan gives you three things at once: a low rumble, a mechanical whirr from the motor and blades, and moving air. Brown noise is the rumble on its own, whirr taken out, no hiss added. Plenty of fan sleepers find that's the bit they were listening for all along.

If it's the real fan you're missing, our Bedtime Fan app plays recordings of actual fans rather than a synthetic stand-in. If your ears want something a touch brighter than rumble, the classic hiss lives over at WhiteNoise.com.

After White Noise, Pink Noise, Rain, Ocean, or Fan Sounds Instead?

Brown noise is the deepest sound going, but it's only one of many. Every pair of ears is different; if yours want something brighter, our app is worth a look. It's got more than 400 sounds, from pink noise to box fans, ocean waves and thunder, with a new one added every week. Mix them together and take your mix anywhere.

If your ears want a brighter, steadier hiss, WhiteNoise.com plays it free, right there in your browser.

Every study behind this page, graded for what it shows and what it doesn't, is laid out in full at slumberstudios.com.

Sources: Stanchina et al. 2005 · Basner & McGuire 2018 · Riedy et al. 2021 · Capezuti et al. 2022 · Awada et al. 2022 · Beninati et al. 1999 · Sereda et al. 2018 · Nigg et al. 2024 · Basner et al. 2026 · Vazzaz et al. 2026. General information, not medical advice — if sleep is a nightly struggle, that's a conversation worth having with a doctor.