Listen to the Rainbow

Every December, millennials like me look forward to seeing our yearly music listening preferences “wrapped” on a popular music streaming app. We share our top five most-listened-to songs on social media, with the idea that our favorite music says something about the kind of person we are.

Imagine my surprise when one year, my most-played song wasn’t a song at all, but a three-hour track of … white noise.

Even if you’ve never purposefully listened to white noise, or other color noises, you’re likely familiar with its sound. Whirring fans, humming refrigerators, staticky radios, pitter-pattering rain, roaring waterfalls—these are all forms of color noise, or what we call sound that is distributed with a continuous signal.

Listening to color noises can improve sleep, increase focus, and enhance learning capacity—hence the reason I had been playing it on a loop while crunching at the computer.

Listen to the rainbow

Noise “colors” are distinguished from each other based on their spectral density—in essence, the way that the power contained by the noise signal is distributed over different frequencies. More simply, this refers to the variation in the location on the sound spectrum the noise’s energy concentrates, which subtly changes how the human ear perceives the signal.

Pink noise has more energy concentrated at the lower end of the spectrum—so it sounds like white noise with a lower, deeper rumble. It’s for this reason that much of what we think of as white noise (including the sound made by white noise machines and white noise soundtracks) is actually pink noise—it’s less grating to our ears and minds.

Brown noise, short for Brownian noise and sometimes also called red noise, is a deeper sound more reminiscent of ocean waves.

Green noise has a similar frequency to white noise but with sounds that are more like nature and less like TV static.

Violet noise and grey noise also have variations of these traits. However, experts say that categorizing sound isn’t an exact science, so the differences between color noises aren’t firmly established and their sounds may overlap.

White noise is a uniform mixture of all frequencies detectable by the human ear. Calling noise “white,” therefore, is a nod to the color spectrum, as white light emits all pigments of light at equal intensity.

Bringing the noise may have benefits

So, what happens when we listen to color noise? More research is needed to fully understand its impacts on our brains, but one scientific theory, called stochastic resonance, posits that white noise can help us tune out external stimuli and unhelpful internal chatter to focus on other stimuli more clearly.

And in our non-waking hours, the theory is relatively simple: by maintaining a level of background noise, we will be less sensitive to sudden sounds that could disturb us during the night.

One needs only to look at TikTok, Spotify, or YouTube to see that color noise has a dedicated and growing body of fans. People comment that color noise has helped them to focus, lessen stress and anxiety, and improve sleep.

For neurodivergent people, including those with reading disabilities and/or ADHD, color noise can offer additional benefits, helping them to better concentrate and complete academic tasks. Studies have also shown improved cognitive performance for neurotypical patients listening to white noise during word-learning exercises.

The science behind the benefits of color noise on sleep has thus far been mixed: while one study found that playing pink noise overnight led to deeper sleep and fewer sleep disruptions, another review of multiple studies found limited evidence that white noise can improve sleep.

Personally, I’ve found that turning on a white noise machine before getting some shut-eye has vastly improved my sleep quality, mainly by drowning out my dog’s (and occasionally, my husband’s) snoring sounds. Color noise may even help babies sleep, says Laurence Bonnemort, a child psychiatrist based in France.

The potential benefits of listening to color noise are not restricted to one type of noise or the other—preferences may be highly personal.

Start listening

If you’re intrigued by the concept of color noise, it’s easy to start bringing it into your life and identifying which shades you like best. Try plugging in a pink noise machine while you’re sleeping or putting on a brown noise track during your afternoon report-writing session.

Color noise also works while on the move: if you feel overwhelmed by the sounds of the city during your commute, listening to color noise in your headphones can be a great way to tune out and relax.