Brown noise for sleep: what it is and what the research says

What brown noise actually is

Brown noise energy falls fast with frequency; a low rumble (distant surf, a waterfall, an aircraft cabin). In engineering terms its spectrum falls 6 dB for every doubling of frequency, which is why it sounds deep, like distant surf. The other two colors are shown faintly on the chart for comparison.

What the research shows

Brown noise has almost no sleep research of its own — most studies use white or pink noise. Its appeal is practical: the low rumble masks traffic and voices without the hiss of white noise, which some people find harsh. The 2021 systematic review (Riedy) covers continuous noise in general and rates the evidence as low quality; treat brown noise as a comfort choice rather than a proven aid.

How to use it tonight

Keep the level low — enough to blur a passing car, not enough to notice. Most people do better with a sleep timer than with sound running all night: once asleep, a change in sound later can wake you, and the research on all-night noise is mixed. If brown noise feels harsh, try ocean or underwater recordings, which lean brown.