The use of white noise has been around a long time in trying to sooth a fussy baby or drown out the hum of a big city. It has also been used with great success to help reduce the bothersome symptoms of tinnitus, i.e., the perception of ringing in the ear. But what exactly is white noise, and how does it help you relax?
Man staring at static TV with white noise

What is White Noise?

The term "white noise" refers to sounds that are used to mask other, naturally occurring sounds in your environment. White noise machines can produce sounds that are similar to a bedroom fan, the hum of an air conditioner or a soft static from a radio. With its equal power across all ranges, it is quite monotonous, which helps your brain ignore high-pitched, or other unpleasant sounds.

To understand what white noise is, we have to take a closer look at what sound waves are made of. If you could take apart a sound wave, you would find two fundamental elements:
  • Frequency, which is how fast the waveform is vibrating per second. Humans can normally hear frequencies ranging from 20 to 20,000 Hz (Hertz)
  • Amplitude, which indicates the size of the waves. Amplitude is another way of saying how loud the sound is.
diagram explaining the frequency and amplitude of white noise sound waves
White noise derives its name similarly to white light. While white light contains all the frequencies of visible colors, white noise contains all the audible frequencies.

If you live in the city, you know exactly how irritating the sounds of traffic can be, especially when you try to fall asleep at night. Some people turn on a fan, more so for the calming sound than the air it moves. The hum of the fan is white noise and can help cancel out some of the unwanted sounds in your surroundings and help you drift off to sleep.

If you are wondering right now if there is any evidence to any of these benefits, the answer is yes. According to one study, white noise can be especially helpful with putting newborn babies to sleep. You can find various types of sound machines to help your baby sleep.

White, Pink, Brown, Violet Noise

You may be surprised to learn that depending on the intensity and frequency range, white noise can be divided into several other noise colors. Some of the examples are:
Pink noise is the same as white noise, but with reduced higher frequencies. It is louder at the low-frequency end of the spectrum and softer at the higher end. Listening to it while sleeping can improve your memory of the following day.
Brown noise is even stronger and deeper at the low end without the high-frequency sounds of pink and white noise. It can help you relax, focus, and improve your sleep.
Blue noise is sometimes considered high-frequency white noise. It is a noise color with a spectral density that is proportionate to its frequency. Blue noise raises in volume with increasing frequency, but at a lower rate than violet noise.
Violet noise is a type of sound that increases in volume at higher frequencies. It is also known as purple noise. It is particularly beneficial in blocking some higher frequency sounds associated with tinnitus.

Can I Relax with White Noise?

Having a perfectly silent bedroom is often impossible. Noises from neighbors' dogs, construction equipment, nearby trains passing or typical traffic can creep into your room and keep you from falling asleep. And because hearing continues through the night, it may be necessary to give your brain something to easy focus on to calm your system down.

White Noise Machines

So what if you can not fall asleep, or struggle to focus on work or study? Purchasing a white noise machine at a store or online may be a good solution to your problem. White noise machines produce soothing sounds and should help improve your sleep quality. Besides improved sleep, you may find that it helps reduce stress, increase your focus, soothe headaches and migraines, and mask tinnitus (ringing in the ears). Due to its soothing properties, white noise has also been also used in hypnosis.

How Does It Work?

Several explanations exist for why white noise works. One theory is that the louder the environment, the less sensitive the ears become. For example, a dripping faucet likely does not bother you during the day. At night, however, when everything is quieter, it becomes annoying. White noise raises the threshold again, and the dripping tap or other sounds are no longer audible.

White Noise Apps

According to another theory, the brain is always on the lookout for (acoustic) stimuli. The steady noise "occupies" the brain, without overwhelming it. It is too monotonous for that. Many report positive results using free versions of white noise apps on their smartphones. One example is the White Noise Lite app, which produces white or pink noise (available for Android and Apple).
This and other similar apps do an excellent job of combating different bothersome background sounds and creating an ambient environment. Most apps include most color noises (brown, white, pink, etc.), mechanical sounds like a bedroom fan or air conditioner, light to heavy rains, rushing water sounds, beach and ocean waves. Be sure to download the latest version to get the best possible experience. Turn on the app at night and let it play in the background as you drift off to sleep.

White Noise for Babies

White noise generators are very popular with parents of small children. The reason for the popularity is that the monotonous sound reminds babies of being in their mother's womb, which in turn has a calming effect. Babies, as early as the 6th month of pregnancy, can hear various subtle sounds, such as muffled tones of the heartbeat of their mother.

Parents should be mindful of setting the volume at an appropriate level. Speakers emitting sounds up to 80 decibels (dB) loud are at the same level as a hairdryer or a vacuum cleaner. Remember to set speakers a good distance from a child and that white noise should be a subtle background noise.