You may have heard of white noise being used to mask background sounds. Now there is colorful competition in it.
There is a growing discussion about pink noise, brown noise, green noise – a rainbow of soothing sounds – and their theoretical effects on sleep, concentration and the relaxation response. (Also read: What is green noise? Know its benefits for sleep and mental health)
This science is new and there have only been a few small studies behind it, but that hasn’t stopped thousands of people from listening to these sounds for hours on YouTube and meditation apps, which offer a range of colorful sounds with a paid subscription.
What is pink noise?
To understand pink noise, start with white, the most familiar of the colored noises.
White noise is similar to the static noise on the radio or TV. Sound engineers define it as equal volume across all frequencies heard by the human ear. It gets its name from white light, which includes all visible color wavelengths.
But the higher frequencies of white noise can sound harsh. Pink noise turns down the volume on those high frequencies, so it sounds lower in pitch and more like the natural sound of rain or the ocean.
Brown noise has an even lower pitch, making it a pleasant, soothing purr.
Pink and gray, like white, have standard definitions for audio experts. Other color noises are recent creations with very flexible definitions.
What is the science behind color noise?
According to a recent review of limited ADHD studies, white noise and pink noise may provide small benefits for people with attention-deficit/hyperactivity disorder. In theory, it wakes up the brain, said co-author Joel Nigg, an ADHD researcher at Oregon Health & Science University in Portland.
“Noise provides stimulation to the brain without providing information, and therefore is not distracting,” Nigg said.
White noise is used to treat ringing or buzzing in the ears, called tinnitus.
Scientists at Northwestern University are studying how short waves of pink noise can enhance the slow brain waves of deep sleep. In small studies, these pink noise waves have shown promising results in improving memory and relaxation response.
Dr. Ronil Malkani, associate professor of neurology at Northwestern University Feinberg School of Medicine, said the frequency profile of pink noise is “similar to the distribution of brain wave frequencies that we see in slow-wave sleep because these are larger, slower waves.”
If Northwestern’s research is successful, it could lead to the creation of a medical device to improve sleep or memory through personalized pulses of pink noise. But many scientific questions remain unanswered, Malkani said. “We still have a lot of work to do.”
Is there any harm in trying colorful sounds?
If colored noises feel calming and help you block out distractions, it makes sense to use them. Of course, keep them at a quiet level to prevent hearing loss and “take ample breaks to rest the ears,” Nigg said.
