Free Noise Machine
Mix white, pink, brown, green & black noise — generated live in your browser.
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What do the noise colors mean?
White Noise
White noise contains equal energy at every audible frequency — roughly like a hissing TV or air conditioning unit. Its broad spectrum makes it effective at masking variable sounds (conversations, traffic) because it covers a wide range at once.
Best for: masking office noise, general focusPink Noise
Pink noise rolls off 3 dB per octave from high to low frequencies, so each octave carries equal power. It sounds warmer than white noise — like steady rainfall or a fan. Many people find it easier to listen to for extended periods. It is sometimes described by researchers studying sleep as a candidate for improving slow-wave sleep, though evidence is still emerging.
Best for: sleep, relaxation, long focus sessionsBrown Noise
Brown noise (also called red noise) rolls off 6 dB per octave — a steeper fall than pink — producing a deep, low rumble similar to ocean waves, distant thunder, or a large waterfall. It is the warmest and lowest-pitched of the common noise colors. Anecdotally popular for sleep and for people with ADHD who find it easier to concentrate with a low bass hum present.
Best for: deep sleep, focus, tinnitus masking at bass frequenciesGreen Noise
Green noise is shaped around the middle of the audible spectrum (roughly 100–800 Hz) and is often described as resembling the ambient sound of nature — a meadow on a calm day, light wind through leaves. It lacks the high-frequency edge of white noise and the sub-bass weight of brown, sitting in a comfortable middle register useful for focus without fatigue.
Best for: ambient focus, nature-like atmosphereBlack Noise
Black noise is near-silence: only very-low-frequency sub-bass energy below roughly 80 Hz, far below the range of most environmental sounds. At low volumes it creates a barely-audible rumble or pressure sensation. Blend a small amount with brown for added depth, or use it alone for a grounding, near-silent listening environment.
Best for: depth blending, minimal sensory environmentFrequently asked questions
What is the difference between white, pink, and brown noise?
White noise has equal energy at every frequency — it sounds like hissing static. Pink noise reduces energy by 3 dB per octave as frequency rises, giving a warmer sound like rainfall. Brown noise rolls off at 6 dB per octave, creating a deep rumble like ocean waves. Green sits in the mid frequencies (100–800 Hz) for a nature-like ambient texture. Black noise is near-subsonic rumble — mainly felt rather than heard.
Which noise color is best for sleep?
Brown and pink are the most commonly recommended for sleep because their lower-pitched texture is less fatiguing and masks the sudden sounds (voices, traffic) that disrupt sleep most effectively. The Sleep Foundation notes that consistent background sound can help some people fall asleep and stay asleep by reducing auditory contrast. Personal preference matters — try brown at medium volume, or add a touch of green, and adjust to what feels comfortable.
Is this noise machine free? Are there any time limits?
Completely free, with no ads and no account required. There are no time limits on this web tool — you can run it all night. All five noise colors are generated live in your browser via the Web Audio API; no audio files are downloaded. The BrainSync app (iOS and Android) extends this with saved mixes, binaural beats, guided sleep programs, and more.
Does a noise machine work without headphones?
Yes. Unlike binaural beats (which require a separate tone in each ear), noise works equally well through laptop speakers, a Bluetooth speaker, or any stereo or mono output. Headphones give a more immersive and private experience, but a speaker at moderate volume in your bedroom will mask ambient sounds just as effectively.
Can noise help with tinnitus or help me focus?
Many people with tinnitus find that background noise partially masks the ringing, reducing how loud or intrusive it feels. White and pink noise are commonly mentioned for this by audiological organizations including the Cleveland Clinic, though individual responses vary and noise is not a medical treatment. For focus, a steady mid-range noise (white or green) can reduce distraction from variable background sounds in offices or cafes — similar to the way some people work better in a busy coffee shop than in silence.