Brown Noise vs. White Noise: Which Is Best for Quality Sleep?

Brown noise (also sometimes called red noise) is the deeper cousin of white noise, with a sound profile that emphasizes lower frequencies while minimizing higher frequencies. Natural brown noise sounds like roaring river rapids, heavy rainfall and distant rumbling thunder, which many find pleasing to the human ear.

This type of noise is named not only for a color, but also for Scottish scientist Robert Brown.

In the 1800s, Brown observed pollen particles moving randomly in water and devised a mathematical formula to predict these movements. When this randomizing formula is used to generate electronic sound, a bass-heavy noise profile results.

White noise, on the other hand, covers all the frequencies, from low-frequency bass notes to high-frequency chimes. It effectively masks sound inconsistencies, helping you drift into a peaceful slumber.

Natural occurrences like sprinkling rain or a gentle breeze rustling through trees can be considered forms of white noise.

Pink Noise: A Gentle Alternative

Your choices aren't limited to brown and white noise, however. There's also pink noise, which might be the answer to quality sleep. A study at Northwestern University linked pink noise to deeper sleep and enhanced word recall in older adults.

Pink noise is akin to white noise but leans more towards bass and mid-range tones, resembling sounds like moderate rainfall or ocean waves. Those who prefer lower-pitched sounds might find pink noise more pleasing to the ear.

There's still a great deal that science doesn't quite understand about human sleep patterns, and the studies on auditory stimulation and sleep have used very small sample sizes.

One 2017 experiment at Oxford University on eight sleepers found that subjects fell asleep around 40 percent faster while listening to white noise. Overall sleep time was mostly unchanged, though.

A 2016 study showed that 16 young adults had slightly improved recollection of vocabulary words if they slept under pink noise. And another 2017 study at Northwestern University (of 13 older adults) linked pink noise with deeper sleep and improved ability to recall words.

A larger study conducted by the Journal of Caring Sciences in Iran looked at 60 elderly coronary patients, with half of them sleeping under white noise and half with regular hospital ambient sounds.

In the control group, scientists found that quality of sleep degraded as the patients spent multiple nights in the hospital with the typical distracting sounds. For those getting the white noise treatment, however, quality of sleep remained roughly the same throughout their stay.

We were unable to find any research studies on the effects of brown noise on sleep. The effects of brown, white and pink noise will most likely remain subjective until experiments can be conducted with larger sample sizes and a more diverse array of participants.

There are plenty of free and paid options available to try all the various colors for sleep. You can find natural and synth tracks on streaming services like YouTube and Spotify. There are also dedicated mobile apps for sleep assistance, which can provide a more curated selection of audio.

You can also buy a purpose-built sound machine, usually with integrated speakers and a multitude of noise profile options. Many of these have timer functions, to play noise as you fall asleep and then turn themselves off after an hour or so.

Whatever the audio source, you'll want to set the volume on the lower end to blend in with regular background ambience. Overly loud noises or background noises can make sleep quality worse, so it's best to apply white, pink or brown noise conservatively.

While science offers some insights on which noise color is best for sleep, personal preference ultimately plays a significant role in selecting the color that suits you best. You can even experiment with a blend of these noise colors to create a custom sleep soundscape that resonates with your senses.

According to Dr. Phyllis Zee of Northwestern University Feinberg School of Medicine, there's not a definite answer. "What I tell my patients is, 'I really don't know which is going to be better. Why don't you just try them out to see which is relaxing for you?'" Zee was one of the researchers in the 2017 study of pink noise and older adults.

Sleep is a vital aspect of our lives, and finding the right noise color for you might just be the key to unlocking a world of deeper, more restful nights. Sweet dreams!

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.