What white noise is
It's a random sound where every frequency plays at the same strength. It sounds bright and hissy, like a radio between stations or a running shower.
Next to pink and brown noise, white is the brightest. It's best at covering sharp, high sounds: voices, clattering dishes, beeping gadgets.
Why people use it
Noise doesn't make your surroundings quieter. It raises a steady background, so sudden changes (a door, the neighbours, a passing car) stand out less. The brain reacts to changes, not to a steady sound.
That's why people play white noise to sleep in noisy flats, to work in open offices and to study. The evidence on sleep is mixed: a 2021 review in Sleep Medicine Reviews found few high-quality studies. If it helps you, that's what counts.
How to listen
Keep the volume low, about as loud as a quiet shower in the next room. Loud noise all night is bad for your hearing.
Keep the speaker or phone away from your pillow. Better not to sleep in headphones.
Set the timer for 30 or 60 minutes: the noise fades out once you're asleep.
If white feels harsh, try pink or brown: they're softer and deeper.