Brown noise
A deep, rounded rumble like a distant waterfall or the inside of an aeroplane. Brown noise drops 6 dB per octave, so most of its energy sits in the bass.
- Spectrum
- −6 dB per octave (power falls with 1/f²)
- Good for
- Sleeping through low rumble and traffic
- Long focus sessions without listener fatigue
- People who find white noise too harsh
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What is brown noise?
Brown noise (also called red or Brownian noise) is what you get when a signal takes a random walk: each sample is the last one plus a small random step. The name honours the botanist Robert Brown, who described the random movement of particles in water, not the colour.
Mathematically its power falls with the square of frequency, 6 dB less for every doubling. On the dial the trace slopes steeply down to the right: the bass dominates and the high hiss almost disappears.
Brown noise for sleep
Because it carries so little treble, brown noise masks low-frequency sounds (traffic, neighbours' music, a humming fridge) without the sharp edge of white noise. Many people can tolerate it louder and longer, which makes it popular as an all-night sound.
Brown noise for ADHD and focus
Brown noise went viral on TikTok in 2022 as a focus aid for people with ADHD. The research is thinner than the hype: studies on noise and attention mostly used white or pink noise. Read our honest summary on the brown noise for ADHD page, then try it yourself for a week.
Read: does brown noise help ADHD? · White noise vs brown noise
Questions
Why is it called brown noise?
After Robert Brown and Brownian motion, the random jiggling of particles. Brown noise is the sound of a random walk. "Red noise" means the same thing.
Is brown noise better than white noise?
Not better, different. It masks low sounds well and is easier on the ears; white noise masks high-pitched sounds such as voices more strongly.
Does brown noise help with ADHD?
Some people with ADHD report calmer focus with it. Controlled studies mostly tested white noise and found small benefits for inattentive children and none for others, so it is worth a personal test rather than a promise.
Can I play brown noise all night?
Yes, at a gentle volume. Set the timer if you prefer it to fade out after you fall asleep.
How is brown noise different from black noise?
Black noise usually means silence or near-silence. Our black noise is an almost inaudible sub-bass murmur; brown noise is clearly audible across the whole range.