How to use the noise generator
- Choose a noise color: white, pink or brown. You can switch while it plays; the new sound fades in over half a second.
- Press Play and set the volume with the slider. Start low and raise it only until the sounds that bother you — traffic, a snoring partner, office chatter — blend into the background.
- For sleep, pick a sleep timer of 15, 30 or 90 minutes, 1 hour or 8 hours. The sound holds steady, fades out gently over the last minute and stops. “Off” plays until you press Stop.
The sound is created in your browser — it is not a recording and nothing streams, so it uses no data once the page is open. Browsers that show media controls for web pages list it there, with a pause button.
White, pink and brown noise: what the colors mean
All three are random sound with no rhythm or melody. The color describes how the power is spread across frequencies:
- White noise has the same power at every frequency, like white light. Each octave up contains twice as many frequencies as the one below, so the high octaves get most of the energy: a bright hiss.
- Pink noise (1/f) loses 3 dB of power per octave, so every octave carries the same total power. That matches how we hear pitch, so pink noise sounds balanced — like steady rain or wind in the trees.
- Brown noise (1/f², also called red or Brownian noise, after the random Brownian motion of particles) loses 6 dB per octave. Most of its energy is in the bass: a soft, deep rumble like surf or a jet cabin.
| Color | Spectrum | 100 Hz vs 1 kHz | 10 kHz vs 1 kHz | Sounds like |
|---|---|---|---|---|
| White | flat | 0 dB | 0 dB | hiss, radio static |
| Pink | −3 dB per octave | +10 dB | −10 dB | rain, wind |
| Brown | −6 dB per octave | +20 dB | −20 dB | rumble, distant surf |
How the sound is made
White noise is simply a stream of random numbers. Pink noise passes that stream through Paul Kellet’s filter, a classic sum of simple filters that follows the 1/f slope closely across the audible range. Brown noise is a “leaky” running sum of white noise: each sample keeps most of the previous one and adds a little randomness; below about 40 Hz the slope levels off, because most speakers can’t play lower anyway. The generator makes a 20-second stereo loop and blends its last second into the first, so the loop has no click, and every color is scaled to the same average level.
What the research says — sleep, focus, tinnitus
Steady noise works by masking: it makes sudden sounds, such as a door or a car, less noticeable. Beyond that, the evidence is thin:
- Sleep: a 2021 systematic review in Sleep Medicine Reviews (Riedy and colleagues, 38 studies) rated the quality of evidence that continuous noise improves sleep as very low, and noted that noise may also disturb sleep and harm hearing.
- Pink noise and deep sleep: the often-cited studies (Ngo and colleagues, Neuron, 2013) played 50-millisecond bursts of pink noise timed to brain waves measured by EEG in a sleep lab — not a continuous track from a speaker, so their results don’t carry over to a noise generator.
- Focus and ADHD: a 2024 meta-analysis in the Journal of the American Academy of Child & Adolescent Psychiatry (Nigg and colleagues) found a small benefit of white or pink noise on laboratory attention tasks for people with ADHD or many ADHD symptoms, and a slight negative effect for others. No brown-noise studies were included.
- Tinnitus: the American Academy of Otolaryngology–Head and Neck Surgery guideline (2014) lists sound therapy as an option for persistent, bothersome tinnitus. Talk to a doctor or audiologist about ringing in the ears, especially if it is new or in one ear only.
Volume and safety, especially near babies
A 2014 study in Pediatrics (Hugh and colleagues) measured 14 infant sleep machines at maximum volume: all were louder than 50 dBA — the recommended limit for hospital nurseries — at 30 cm, and three exceeded 85 dBA. The American Academy of Pediatrics advises on HealthyChildren.org: “If you use a sleep machine, place it as far away from the baby’s head as possible and use it for a short time only.” With this page, that means a phone or speaker across the room, never in the crib, a low volume, and a sleep timer.
For everyone: the WHO–ITU safe listening standard (H.870, 2019) sets a weekly allowance equal to 80 dB for 40 hours for adults and 75 dB for 40 hours for children; the louder the sound, the shorter the safe time. A sound that plays all night should be far quieter than that — ideally just loud enough to mask, never loud enough that you have to raise your voice over it. Avoid sleeping in earbuds at high volume.
Also useful at bedtime: the sleep calculator finds wake-up times that fit full sleep cycles.
Frequently asked questions
Which noise color is best for sleep?
Research hasn’t found a winner — the evidence for any noise improving sleep is weak. Many people find brown or pink noise more pleasant for hours of listening because it has less hiss than white noise. Try each for a few nights at a low volume and keep the one you notice least.
Is white noise safe for babies?
The American Academy of Pediatrics advises placing a sleep machine as far from the baby’s head as possible and using it for a short time only. Keep the phone or speaker across the room, out of the crib, at a low volume, and use the sleep timer.
Can I play it all night?
Yes: leave the sleep timer off and the sound loops until you press Stop. Keep the volume low and the device plugged in. Some phones pause web audio when the screen locks or another app plays sound; if that happens, keep this page open in the foreground.
Does it use mobile data or work offline?
The noise is computed on your device, so playing it uses no data. Once the page has loaded it keeps working without a connection.
Last updated: October 15, 2026