If you try to fall asleep, then any extraneous noise can quickly intensify. Noise machines have become popular sleeping tools for masking the squeak of a floor in the next room or the horn of cars outside. While we often summarize all of their regular, fan-shaped sounds as “white noise,” sound and music experts explain that there are actually a lot of different “colors” of sounds these machines make – and white noise is probably the worst for sleeping. Here’s why and what nuances you should look for for your sleep instead.
What is White Noise?
The theory of sound is very mathematical and technical, but in its most basic form, sound is a combination of wavelengths with different frequencies or speeds of vibration. “Noise is a selection of individual frequencies played in a random distribution,” says Greg McAllister, Senior Sound Experience Manager at Sonos, who helps develop the company’s sleep stations for Sonos Radio. “The different types of noise are the way this frequency distribution is weighted over the entire range.”
If all these different frequencies are weighted in the same way, you get real white noise. Daniel Bowling, Ph.D., an acoustics researcher at Stanford and a neuroscience consultant at Spiritune, explains that this equal weighting of frequencies is unnatural. This means it sounds more like the static hum of a machine than anything you would hear if you were walking outside in a forest or beach. (In nature, higher frequencies are not represented as often.)
“White noise is like static television. If you do that very hard, it gets really annoying,” Bowling tells mbg. “High-frequency content will attract your attention, increase your excitement and make you anxious.”
He notes that even though white noise is often considered the gold standard of sleep, the last thing you want to activate is to relax before going to bed.
Which color of noise is better for sleeping.
Other noise colors have different distributions of low and high frequencies – in contrast to white noise, which represents all frequencies evenly. Pink noise is more weighted towards low frequencies, and it tends to be more attractive to our ears. Compared to white noise, McAllister notes that pink noise sounds smoother and warmer. Instead of the high statics of the TV, it is more like the deep hum of the waves that ripple on a beach.
“Brown Noise goes even further, so it is even more weighted towards low frequencies. It may sound more like a rumble or a thunderstorm,” he notes. Because these sounds correlate more closely to what we would hear in nature, McAllister says it makes sense that we find them intuitively comforting.
Pink noise in particular has proven to be deeply relaxing in laboratory studies. When we sleep, our brains are still processing some of the sounds in our environment — our brainwaves can actually synchronize with the frequency of the sounds we hear. Some research has shown that the low and low frequencies of pink noise place our brain in slow-wave states where memory recovery and consolidation can occur. This means that pink noise can go further than masking annoying stimulating noises to improve the overall quality of our sleep and improve our memory.
Most of the white noise machines on the market actually play a spectrum of different noise colors. To get a deeper sleep, you should choose one that falls more into the pink spectrum of noise and sounds like waves on the beach.