You may have heard of white noise used to mask background sounds. Now, there’s a colorful competition.
There is a growing buzz around pink noise, brown noise, green noise – a rainbow of soothing sounds – and their theoretical effects on sleep, concentration and the relaxation response.
The science is new, with only a few small studies behind it, but that hasn’t stopped thousands of people from listening to these noises for hours on YouTube and on meditation apps that provide a palette of colorful noises with paid subscriptions.
WHAT IS PINK NOISE?
To understand pink noise, start with white, the most familiar of the colored noises.
White noise is similar to static from a radio or TV. Sound engineers define it as having equal volume at all frequencies audible to the human ear. Its name comes from white light, which contains all visible color wavelengths.
But the high frequencies of white noise can sound harsh. Pink noise lowers the volume at higher frequencies, so it sounds quieter and more like the natural sound of rain or the ocean.
Brown noise sounds even quieter, providing a pleasant, mellow noise.
Pink and brown, as well as white, have standard definitions for audio experts. Other color noises are more recent creations with very flexible definitions.
WHAT IS THE SCIENCE BEHIND COLOR NOISES?
White noise and pink noise may have small benefits for people with attention-deficit/hyperactivity disorder, according to a study. recent review of limited ADHD studies. In theory, this wakes up the brain, said ADHD researcher and co-author Joel Nigg of Oregon Health & Science University in Portland.
“Noise stimulates the brain without providing information and is therefore not distracting,” Nigg said.
White noise has been used to treat tinnitus or ringing in the ear, called buzz.
Scientists at Northwestern University are studying how short pulses of pink noise can improve slow brain waves from deep sleep. In small studies, these pulses of pink noise have shown promise in improving memory and the relaxation response.
Pink noise has a frequency profile “very similar to the frequency distribution of brain waves that we see in slow-wave sleep because they are large, slow waves,” said Dr. Roneil Malkani, assistant professor of neurology at the Feinberg School of Medicine at NorthwesternUniversity.
If the Northwestern research comes to fruition, it could lead to a medical device to improve sleep or memory through personalized pulses of pink noise. But many scientific questions remain unanswered, Malkani said. “There is still a lot of work we have to do.”
IS THERE ANY HARM IN TRYING COLOR NOISES?
If colored noises are calming and help drown out distractions, it makes sense to use them. Keep them at a quiet level, of course, to prevent hearing loss, and take “plenty of breaks to let your ears rest,” Nigg said.
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