Noise generator. White, pink or brown, for focus, sleep or testing. Free, in your browser.

Questions

What's the difference between white, pink and brown noise?

White noise has equal energy at every frequency, so it sounds bright. Pink noise falls by 3 dB per octave, giving each octave equal energy, which sounds more balanced. Brown (or red) noise falls by 6 dB per octave, so it is mostly low rumble.

Which is best for sleep or focus?

It's personal. Many people find pink or brown noise easier to listen to for a long time than white, because it has less hiss. Research on noise and sleep or concentration is mixed, so try each at a low level and keep the one you like.

Can I use it to test speakers or a room?

Yes. Pink noise is the usual test signal for setting speaker levels and checking frequency response with a real-time analyser, because it reads flat on an octave-band display.

Will it keep playing with the screen locked?

On a computer it keeps playing in a background tab. Phones may pause audio when the screen locks or the browser goes to the background; keep the page open in front if that happens.

Is it free?

Yes, with no sign-up. The noise is generated in your browser; nothing is downloaded or uploaded.