(Last Updated On: March 30, 2023)

What is White Noise?

A guide to the various color noises and how they can benefit you.

When we think about going to sleep, we often think everything should be as quiet as possible. But research is proving that is not necessarily the case. Pairing the word “noise” with sleep seems counterintuitive, but there are particular types of noise that can actually help you get a better night’s rest. Certain types, or “colors,” of noise can help you go to sleep, stay asleep, and achieve deeper, better sleep.

A lack of quality sleep can do more than make you feel tired. Sleep deprivation can make it difficult to focus and increase your risk of several health issues, including depression, diabetes, and obesity. It’s important that you get enough quality rest.

By Becky Dotson

5 min read

color bars representing color noise

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Why Is It Called White Noise?

If you break apart a sound wave, you will have two fundamental characteristics. One is frequency, which is how fast the waveform vibrates per second. The other is amplitude, which is the size of the waves. The way they combine gives particular noises their color designation. Noise and its corresponding colors are used in audio engineering, electronics, physics, and several other fields.

Naming different types of noises after colors started with white noise. It is a noise that contains all frequencies that humans can hear equally. Noises are named similarly to the colors of light. White light has all the audible frequencies we can hear, much like white light has all the frequencies we can see.

What Do The Colors of Noise Sound Like?

White Noise
So, what does white noise sound like? White noise is often compared to the static sound that comes from an untuned radio or TV. In nature, it’s similar to the sound of a big waterfall. It’s a consistent, steady sound that helps mask other, intermittent noises.

Studies have shown that white noise can actually help you fall asleep. A 2017 study found that participants falling asleep nearly 40% faster while listening to white noise. A separate study found it helped improve and maintain sleep for patients in a hospital’s coronary care unit. Researchers have also found white noise improves work performance and helps reduce crying in babies. There’s also the possibility it can help counteract symptoms of attention deficit hyperactivity disorder (ADHD).

Pink Noise
Some types of noises are considered to be pink. Pink noise is a combination of all frequencies we can hear, but the energy isn’t equally distributed. Pink noise has a lower pitch than white noise and the soundwaves filter out higher sounds. Its pitch is even and flat and it creates a deeper sound that some people find more relaxing or soothing. Heartbeats, rustling leaves, steady rain, waves on the beach, and wind are all examples of pink noises.

According to research from the University of Pennsylvania, pink noise can help you go to sleep and might even improve your memory, as memories are stored during deep sleep. Pink noise has started to emerge in research settings as more beneficial than white noise in helping someone get to sleep.

Brown Noise
Brown noise, which is also called red noise, has a deeper frequency than pink or white noise. With brown noise, the lower frequencies will be louder and the higher ones will be softer. Brown noise is similar to thunder, a low roaring, heavy rain, or the steady hum of an airline jet.

Other Colors of Noise

Green Noise
Green noise covers the middle frequencies of the sound spectrum. It sounds a lot like being on a busy street or the background noise of fans at a sporting event. Green noise is ambient and is sometimes referred to as “the background noise of the world.”

Blue Noise
Blue noise, also called azure noise, has all the audible frequencies on the sound spectrum, but the higher pitched ones are more amplified. Blue noise is harsh compared to white, pink, and brown noise. It is similar to the sharp hiss you hear when a water hose has a kink in it.

Violet Noise
Violet noise is also called purple noise. It’s higher pitched and is sometimes referred to as blue noise’s more intense cousin. When the frequency goes up, the power and volume go up in violet noise. It can be compared to the sound of a fully open water faucet. Violet noise can be used to treat tinnitus – a condition that causes ringing in the ears.

Orange Noise
You may love the color, but you likely won’t appreciate the noise associated with the color orange. It’s often described as an ensemble or band that is out of tune. Orange noise includes clashing sounds and generally is not pleasant to the ear.

Gray Noise
Gray noise is similar to white noise, but it produces sound at higher and lower frequencies, and not many in the middle. It sounds like loud static or the sound of a shower running.

Black Noise
With the exception of some thin bands and spikes of random noise, black noise describes the lack of noise or the sound of silence.

What Color of Noise Is An Air Purifier?

Several companies make sound machines that produce a consistent white noise sound to help people sleep. Air purifiers, also, have begun to incorporate color noises into their products.

Air purifiers help clean and purify the air, and are often bought to go in the bedroom, which makes them the perfect appliance to use as a white or pink noise machine.

Air purifiers run on electricity and use a fan to filter harmful particles out of the air. All air purifiers are therefore going to make noise of some type. Many air purifiers will be equipped with a sleep mode or whisper quiet fan speed. This is the equivalent, in many cases, to white noise. Some air purifiers emit pink noise – which, as mentioned, is white noise with the bass cranked up. According to recent research, this lower rumble is proving to be even more effective than white noise in helping you go to sleep and stay asleep.

One air purifier that produces pink noise is the Alen BreatheSmart 45i. It makes pink noise on all four fan speeds and has been given a SleepScore rating. SleepScore is an independent lab that tests products to determine if they are effective at helping people go to sleep and stay asleep. The lab has tested the 45i and the results showed it can help people achieve better sleep, as well as alleviate allergy symptoms.


If you’re having trouble sleeping, it could be the noises you’re hearing at night or the air you’re breathing or both. Finding an air purifier with a consistent, low, steady hum could solve the problem by helping you breathe easier and sleep better.

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