White Noise

White noise is a broadband sound signal containing every frequency in the audible range (20 Hz to 20,000 Hz) at approximately equal intensity. The name comes from an analogy with white light, which contains all visible wavelengths. In practice, white noise sounds like sustained static, a rushing waterfall, or a fan running at constant speed. It's the most widely used type of sound masking for sleep, infant soothing, tinnitus relief, and workplace privacy.

How White Noise Works

White noise aids sleep and concentration through auditory masking. Your brain constantly monitors environmental sounds for threats — a creaking floor, a car horn, a voice — and each novel sound triggers a micro-arousal that can fragment sleep or break focus. White noise raises the baseline sound floor so that these intrusions become imperceptible by comparison. A 2005 study in Sleep Medicine found that ICU patients exposed to white noise fell asleep 38% faster and experienced fewer awakenings than a control group in the same noisy environment.

White Noise for Sleep

White noise is the most-studied sound masking approach for sleep. Research consistently shows it reduces sleep onset latency (time to fall asleep) by 20–40% in noisy environments. However, some people find pure white noise too "hissy" or harsh because of its equal emphasis on high frequencies. If that describes you, consider pink noise (which rolls off the highs) or brown noise (which is even deeper and warmer). The best noise color for sleep is whichever one you find most comfortable — all three mask environmental sounds effectively.

White Noise for Babies

White noise is widely used to help babies sleep, and pediatricians generally consider it safe when used correctly. The American Academy of Pediatrics recommends keeping any sound machine at 50 dB or below (roughly the volume of a quiet conversation) and placing it at least 200 cm (7 feet) from the crib. A 2014 study in Pediatrics tested 14 popular infant sound machines at maximum volume and found that all exceeded 50 dB at crib distance — the takeaway is to keep the volume well below maximum. White noise mimics the constant whooshing sound of blood flow that babies hear in the womb, which is why it's effective at calming newborns.

White Noise vs Other Sound Colors

White noise is the brightest and most high-frequency-heavy of the noise colors. Pink noise sounds more balanced and natural (like rainfall), while brown noise sounds like a deep rumble (like distant thunder). For a detailed comparison, see our brown noise vs white noise guide. Beyond the color noises, many people prefer rain sounds or nature sounds — these are technically colored-noise-like signals with natural variation that some listeners find more pleasant than synthetic noise.

White Noise and Tinnitus

Audiologists frequently prescribe white noise or white noise generators as part of tinnitus retraining therapy (TRT). The principle is the same as sleep masking: a constant external sound reduces the perceived loudness and intrusiveness of the internal ringing. TRT combines white noise exposure with cognitive behavioral therapy over 12–24 months. A 2019 Cochrane review found moderate evidence that sound therapy (including white noise) reduces tinnitus severity, though no single approach works for everyone. For people with both tinnitus and sound sensitivity, volume should start very low and increase gradually.