Ahh, the sweet music of car horns honking, upstairs neighbors stomping and even your partner snoring loudly next to you in bed: Seattle’s late-night lullaby.
Hearing loud, random sounds can startle your brain and disrupt your sleep patterns, preventing you from feeling well rested.
While white noise has long been held as a magic bullet for blocking out these erratic sounds, there’s a new sonic color that’s making waves.
Pink noise, a mix of high and low frequencies, is often considered more soothing and easier to listen to than the better-known white noise. But what actually is it?
Here’s what you need to know about pink noise and how it compares to other sonic hues.
What is pink noise?
Pink noise is a category of sounds that contains all the frequencies that a human ear can hear, or 20 Hz to 20,000 Hz, says Iris Langman, MSPA, a clinical audiologist at the UW Medicine Northwest Outpatient Medical Center.
Although pink noise contains all of these frequencies, we don’t hear all of them equally. This is because the higher frequencies in pink noise are less intense — a phenomenon that replicates the way humans hear sound.
Because pink noise mimics how we hear, acoustical engineers originally used it to equalize loudspeakers and instruments at concerts, testing for any shrill or tinny pitches that would sound bad to an audience. Recently, pink noise has taken center stage itself as it’s become a favorite of those who want to mask unwanted sounds when they are trying to sleep or work.
What is the difference between pink noise and white noise?
White noise, like pink noise, is a masking sound that contains all the frequencies that humans can hear.
The difference is that all of the frequencies in white noise have the same intensity — meaning amplitude or power — throughout the spectrum, while in pink noise, the higher frequencies are less intense than the lower frequencies.
Because humans are more sensitive to high pitches (think crying babies or car alarms), we hear more of the high frequencies in white noise, even though they are the same intensity as the low frequencies. This makes white noise sound higher pitched and brighter, like a whirring fan or vacuum.
In contrast, the high frequencies in pink noise are less intense, so pink noise tends to be lower pitched and steady, like wind rustling through leaves in a tree, steady rainfall or waves hitting the shore.
“Pink noise reduces the high pitches of white noise and becomes a more pleasant sound,” Langman says. “It’s gentle because you are hearing more of the lower frequencies.”
Can pink noise help you focus or sleep better?
There is still a lot to learn about whether and to what extent pink noise aids sleep.
In 2012, an early study found that pink noise could help create more stable sleep. And more recently, a small, preliminary 2017 study found that listening to short bursts of pink noise in a looped pattern can enhance deep sleep.
But these initial studies are imperfect, and much more research still needs to be done, says Dr. Nathaniel Watson, the director of Harborview Sleep Clinic, co-director of UW Medicine Sleep Center and a UW Neurology professor.
While the studies show some promising results, they are limited by the small number of participants and the fact that these participants knew they were listening to pink noise, which can cause a placebo effect and create biased results.
“Your perspective on the quality of your sleep has a significant impact on how you feel,” Watson says. “If you think that the pink noise has helped you, that may be more powerful than whether or not this has been objectively proven.”
So, what does this all mean?
More research needs to be done before doctors and scientists will be prescribing pink noise as a sleep aid, but if you like the sound and find it soothing, feel free to use it to block out other background noises.
And if you’re looking to improve your sleep quality, Watson recommends relying on good sleep habits.
“Whether you listen to white noise, pink noise, no noise or a fan, we know consistency and sleep habits are crucially important to healthy sleep,” he says.
To catch some z’s and feel well rested, focus on going to bed and waking up at roughly the same time every day, avoiding naps, stopping your caffeine intake after 2 p.m. and following a consistent nighttime routine.