What Is White Noise?

By: Nicole Antonio  | 
A scrambled tv channel.
White noise is a type of noise that is produced by combining sounds of different frequencies. Jeffrey Coolidge / Getty Images

We sometimes use the term "white noise" as a catch-all for ambient noises that drown out different sounds. But it turns out there's something special about this particular combination of frequencies — experts have even found that the soothing sound of white noise helps people stay asleep. Buckle up for a primer on different types of ambient noise and how they affect your daily life.


What Is Ambient Noise?

Ambient noise refers to the all background noise that reaches the human ear. It's like the natural soundtrack of the world we live in, consisting of a mix of various sounds, such as the hum of traffic, chirping birds, rustling leaves, distant conversations or the gentle patter of steady rain.

Imagine yourself in a bustling city park or near a flowing river; the collective blend of these sounds creates the environmental noises unique to that setting. Ambient noise is diverse and dynamic, reflecting the character of a specific location. It sets the tone of our surroundings and can have both calming and invigorating effects on our senses, enriching our experiences as we go about our daily lives.


What Is White Noise?

White noise refers to noise that is produced by combining of all audible sound frequencies. If you took all of the imaginable tones that a human can hear and mashed them together, you would have white noise.

The adjective "white" is used to describe this type of noise because of the way white light works. White light is light that is made up of all of the different colors (frequencies) of light combined together (a prism or a rainbow separates white light back into its component colors). In the same way, white noise is a combination of all of the different frequencies of sound. You can think of white noise as 20,000 tones all playing at the same time.


Masking Unwanted Noise

Because white noise contains all frequencies, it is frequently used to mask other sounds. If you are in a hotel and voices from the room next-door are leaking into your room, you might turn on a whirring fan to drown out the voices. The fan or a humming air conditioner can approximate white noise fairly well. Why does that work? Why does white noise drown out voices?

Here is one way to think about it. Let's say two people are talking at the same time. Your brain can normally "pick out" one of the two voices and actually listen to it and understand it. If three people are talking simultaneously, your brain can probably still pick out one voice. However, if 1,000 people are talking simultaneously, there is no way that your brain can pick out one voice.

It turns out that 1,000 people talking together sounds a lot like white noise. So when you turn on a fan to create white noise, you are essentially creating a source of 1,000 voices. The voice next-door makes it 1,001 voices, and your brain can't pick it out any more.

White Noise as a Sleep Aid

Sleep experts and researchers have studied the relationship between white noise and sleep. A constant sound akin to radio static has been found to have potential benefits for promoting a better night's sleep and improving sleep quality.

When individuals are exposed to white noise sounds while sleeping, the soothing and consistent background noise helps mask disruptive sounds, such as traffic or other disturbances. This masking effect can help prevent sudden noises from waking you up and lead to longer periods of undisturbed deep sleep.

You don't need to hunt down an old school radio to summon those masking sounds. It's not hard to find a white noise machine and or white noise app that meets your needs — some white noise machines even have options for pink or brown noise (more on those in a moment). Many people find that incorporating white noise into their nightly routine can contribute to a more relaxed and restful night's sleep.


Pink Noise vs. White Noise

Pink noise and white noise are two types of sounds that have distinct characteristics. White noise is like a blanket of sound that covers all frequencies equally, creating a hissing or shushing sound. It is similar to the static sound you hear when a radio is not tuned to any station.

Pink noise, on the other hand, emphasizes lower frequencies, giving it a rumbling or rushing quality. It is often compared to the sounds of ocean waves or rain. So, while white noise is evenly distributed across frequencies, pink noise focuses more on the lower end of the sound spectrum.


Brown Noise vs. White Noise

White noise and brown noise are types of sound signals that differ in how their energy is distributed across frequencies.

Picture white noise like a painter's palette with an equal amount of each color, where each color symbolizes a different frequency. It results in a consistent, static-like sound similar to an untuned radio because it has equal power at all frequencies.


Contrastingly, brown noise resembles a scale where the frequency (like a slider) gains more momentum and power as it goes down (decreases in frequency). This drop-off of power at higher frequencies produces deeper sounds, like a low, distant rumbling or a steady wind.

This article was updated in conjunction with AI technology, then fact-checked and edited by a HowStuffWorks editor.


Frequently Answered Questions

What does white noise do?
White noise is used to mask other sounds. It can be used to help people fall asleep, to block out noise from a party or other event or to calm a person who is feeling anxious.
What is considered white noise?
The term white noise is used to describe a type of noise that is produced by combining all of the audible frequencies together. This type of noise is often used to mask other sounds and can be used to help people relax or sleep.