If tossing and turning is a familiar sleep pattern for you, odds are you’ve exhausted countless apps in the quest for a better night’s sleep. While popular go-to sounds include white and pink noise, you may have scrolled through to see another color: brown. But what is brown noise?
It gets its name from Robert Brown, a botanist who first discovered "Brownian motion," aka random particle motion, says Dr. Naina Limbekar, M.D., a sleep neurologist at Boston Medical Center. Compared to white and pink noise, brown is deeper in sound, says Dr. W. Christopher Winter, M.D., neurologist and sleep specialist. He points out that brown has a very deep bass component to it, which can be more soothing to some sleepers. The sound can be compared to a low rumble of thunder, a heavy, consistent rainfall, or a strong waterfall, says Limbekar.
The difference between the sleep-friendly color-coded tones lies in their sound frequency (aka the speed of sound). “The distinct names that are derived for noises like the white, the pink, and the brown are all referring to how the energy of the sound is distributed over different frequencies,” says Limbekar, who explains that the intense frequencies of brown noise manifest as a deep, consistent hum.
As for the other "colors," the energy in white noise is distributed equally across all frequencies, explains Limbekar. It contains more static, which is similar to the background noise fans make, adds Winter. Then pink noise contains more energy at lower frequencies, says Limbekar, that ebb and flow to result in a calming sound similar to the rustling of leaves. Brown noise differs by offering an extra-deep sound that, he explains, sounds really soothing to some (though your favorite sleep noise out of the three all depends on preference).
While there is research regarding the benefits pink noise has on sleep, Dr. Limbekar says there are no research studies on the effects of brown noise. That said, the lack of research doesn’t make anecdotal evidence null: By getting rid of higher pitch sounds, brown noise can be very calming.
If you're looking to try it out for yourself, you can turn to countless brown noise videos on Youtube, along with different sound apps. SimplyNoise is one free app with brown noise options, along with tools that allow you to customize your sleep sounds, or you can try White Noise Lite for a wide range of sounds to snooze to. Or, the next time you experience a huge thunderstorm, try going to bed early to take advantage of that natural brown noise. You just might find that brown makes you forget all about your white noise preference.
Dr. Naina Limbekar, M.D., assistant professor of Neurology at Boston University School of Medicine and sleep neurologist at Boston Medical Center
Dr. W. Christopher Winter, M.D., neurologist, sleep specialist, and author of "The Sleep Solution: Why Your Sleep Is Broken and How to Fix It"