Do you go to bed with earbuds on listening to music or “noise” to help you fall asleep? Do you have a favorite color noise? If that sounds like a question out of Alice in Wonderland, rest assured, you haven’t slipped down any rabbit holes. You have almost certainly heard of “white noise” before, but perhaps you have never heard of “pink noise” or “brown noise.” Well, they are real terms, and they might be able to help you sleep better.
What is white noise?
Let’s start with the basics. If you are anything like me, you’ve heard the term “white noise” for most of your life and never given it much thought. Maybe you just assumed it was a simple expression people came up with to describe ambient noise. You are aware that it apparently helps some people sleep, but beyond that, you’ve never given it much thought.
Though lots of sounds get labeled as white noise, actual white noise is the unified frequency that occurs when every individual frequency that is audible to the human ear is played at the same level. Just as white light is the combination of all colored light frequencies, white noise is the combination of every noise that your ear can perceive. The resulting sound is what is normally described as “static.”
The human ear at its healthiest is capable of perceiving frequencies between 20 and 20,000 hertz (Hz). Sound moves in waves, and a single hertz is the measure of one full oscillation in a second. The higher the Hz number, the more oscillations that are occurring per second. Lower frequency sounds are sometimes called “deeper,” like a bass instrument, while higher frequencies cover the range from human speech to “high-pitched” sounds like birds chirping.
What other color noises are there?
So, if white noise represents all perceptible noise frequencies playing simultaneously, what other kinds of color noises exist?
There are actually a lot of different color noises that cover a wide spectrum of sound. The different colors include pink, brown, blue, violet, and gray. You may see other color noises talked about, but these are the colors that have specific definitions.
Let’s take a closer look at some of these noises.
Pink noise is the most popular alternative to white noise. Pink noise is also made up of all the frequencies that the human ear can perceive, but the lower frequency noises are emphasized so that the overall sound is warmer and less tinny. Pink noise still has a distinctively “static” sound, but it isn’t as harsh on the ears.
Brown noise is similar to pink noise, but taken to an even deeper level. Those low frequency sounds are emphasized to an even greater degree so that the resulting sound is more like a gentle hum. Imagine what you would hear on a quiet night with no humans or living creatures around you, and it might be brown noise.
Blue and violet noise are essentially the polar opposites of pinks and brown noise, respectively. The higher frequencies are increased so that the static sound you hear has a tinnier, harsher sound. This type of noise is used for sound engineering and other technical purposes, but it’s not exactly relaxing.
Finally, grey noise is generally perceived as basically white noise, but it involves a special curve in the loudness of the frequencies to create the illusion that all the frequencies are at the same level. The human brain perceives the true equal frequencies of white noise as not being equally loud, so grey noise essentially tricks the mind.
Why is color noise used for sleeping?
When you go to sleep, your brain stops focusing on outside stimuli long enough for you to loss consciousness. If there is a lot of noise or light, the brain is too stimulated and you will struggle to sleep. This is why we go to bed in darkened rooms. While it’s fairly easy to block out light sources, noises are a bit more difficult.
White noise machines such as the Sound+Sleep High Fidelity Sleep Sound Machine or the Big Red Booster utilize a concept known as sound masking to help block out other background noises that might otherwise keep you awake. By playing every frequency, white noise merges all other background noises into its wall of sound, essentially nullifying them as far as your mind is concerned.
Which color noise is best for sleeping?
You have certainly seen white noise machines sold as sleep aids for years. For most people, that addition of ambient noise to their bedrooms is all they need to get a good night’s rest and feel refreshed in the morning. Still, there are those for whom white noise just doesn’t quite do the trick.
The two most common color noises to use as alternatives to white noise are pink and brown. With their emphasis on the lower frequencies, pink and brown noise retain the noise dampening effect of white noise, but with a gentler, more soothing tone.
Pink noise, in particular, has been shown to provide a more restful sleep than white noise. One study in China found that 75% of participants reported sleeping better with pink noise. For people who have been using a white noise machine for years, pink noise might just offer an even more restful night.
Pink noise: not just for sleep
Further studies on the effects of pink noise have shown another interesting link: it appears to improve memory.
In a small study done at Northwestern University in Evanston, Illinois, researchers had 13 adults, 60-years-old or older, spend two nights in their sleep lab. The participants took a memory test at night, slept wearing headphones, and then took the same memory test the next morning. On one random night, no noise was played through the headphones, while on the other night, bursts of pink noise were played throughout the sleeping hours at irregular times.
Pink noise is unintrusive, so it didn’t awaken the participants, but the brain is still aware of it even while the person is sleeping. On the mornings after listening to pink noise, the participants performed, on average, three times better than they had the night before. On the nights without any special sound, there was no improvement on the morning’s memory tests.
This was a small study, so much larger tests will need to be conducted before any findings can be confirmed. Still, it’s a promising discovery and provides yet another reason why it might be time to give pink noise a chance.
Who knows, you might sleep and remember better.