What are white, pink and brown noises?

Do you ever turn on your air conditioner or television because you need background noise to work or relax? Many find comfort in using sounds like these, called color noises, to mask unpleasant or distracting sounds in our environment. In addition, people may use color noise, like white noise, to improve their focus or help them go to sleep.

While many use color noise in their lives, you may be wondering how each color is different, and which is best for you. Let's take a look:

Why are noises categorized as colors?

Names like "white noise, "pink noise," and "brown noise" relate to how sound engineers describe the sound spectrum and the energy of an audible range of sounds.

“Sound is related to color to better describe the frequency, intensity and variation components,” said Dr. Melissa E. Heche, AuD. “In audio engineering, sound is described in a whole rainbow of colors, each with its own unique properties.”

Using colors to describe noises can help to understand sound frequencies with the color spectrum better. “This information is used for music production, relaxation, tinnitus treatment, auditory processing and integration, and to describe natural rhythms like the human heartbeat,” said Dr. Heche.

White noise

White noise was the first color noise ever established and is labeled as white as it has equal power for all sound frequencies. Also known as broadband noise, white noise encompasses all frequencies across the audible sound spectrum. “Like the color white, which incorporates all of the colors in the visual spectrum, white noise incorporates all of the sounds in the auditory spectrum,” said Dr. Heche. Most people associate white noise with the static from a television or radio. 

Aside from television and radio static, other sources of white noise include the following:

• Fans 
• The hum of an air conditioner
• Radiator 
• Steady running water
• Vacuum cleaner
• Steady rain

May help with cognition and sleep

White noise may provide several health benefits relating to brain function and hearing. A 2017 study revealed that listening to white noise can improve cognitive function in healthy adults with lower attention levels. The study involved 80 participants in a single training session in which they learned the names of twenty novel objects. Half the group did so while listening to white noise, the other half listened to silence. The white-noise group had a higher recall rate than those who learned the phrases without it. 

Another potential benefit of listening to white noise is better sleeping quality. A study examining sleeping troubles of patients admitted into a critical care unit found that using white noise can minimize environmental sounds and improve and maintain sleep. With this in mind, white noise may be helpful for people experiencing sleeping problems or residing in a chaotic environment.

But people with tinnitus should use caution

Tinnitus is a common hearing problem that causes ringing in the ears. The tinnitus sound can vary with each patient but is often described as roaring, hissing, buzzing, or clicking sounds that can affect one or both ears and can have a high or low and soft or loud pitch.

White noise has been used as a treatment method to mask tinnitus symptoms, but the research on its benefits is conflicting. A small 2017 study found that using sound therapy, such as white noise machines, can reduce some of the discomforts that tinnitus can cause in patients with normal hearing.

However, authors of a large review published in a major medical journal on white noise and tinnitus raised concerns that listening to color noise may overstimulate the auditory system, worsen tinnitus and even harm cognition. Instead, "nonrandom" noises like music or speech may work better.

Pink noise

The second most common color noise behind white noise is pink noise. Pink noise is typically associated with relaxing sounds in nature. Pink and white noise share many similarities, as they are audible to the human ear and on the broadband spectrum. However, the lower frequencies of pink noise are more distinguishable than white noise. 

“Pink noise is louder at the low-frequency end of the spectrum and softer in the higher frequencies,” said Dr. Heche. “This results in overall equality in sound energy as frequency/pitch increases in a configuration that mirrors how we hear sound.”

Some examples of pink noise are:

• Rushing river
• Rustling plants or trees
• Ocean waves
• Steady rainfall

Like white noise, studies show that listening to pink noise may help improve sleep quality. One study revealed that using pink noise for acoustic stimulation—the use of sound to encourage a response from the nervous system while sleeping—can enhance sleep quality.

In addition, listening to pink noise may improve memory function in older adults, which may help reduce cognitive decline. A study involving younger men revealed that using pink noise during a memory recall session enhanced their beta and gamma waves, which can help with memory retention. 

Brown noise

Lastly, brown noise is another color noise associated with white and pink noise, though brown noise shares the most similarities with pink noise. “Brown noise is even deeper and stronger in the low frequencies and is without the high frequency sounds that the white and pink noises possess,” said Dr. Heche. “Like pink noise, brown noise also shows an incremental decrease in intensity for each increasing frequency octave.”

What separates brown noise from white and pink noise is that this noise contains deeper, more intense frequencies. “However, there is a steeper decrease—by about 6dB per octave—making the differential between the lower and higher frequencies greater than with white and pink noise; brown noise is a sound with much more low frequency energy,” said Dr. Heche. 

Examples of brown noise include the following:

• A running shower
• Heavy rainfall
• Thunder
• Crashing waves

A 2017 study examining a group of employees in their workplace discovered that using brown noise could improve their concentration levels. The participating employees felt that their capabilities to concentrate and perform their tasks improved while listening to brown noise through earphones. 

Other potential benefits of listening to brown noise are improved sleep and a way to address anxiety symptoms. “Brown noise has also been related to improvements in sleep patterns, but it is also utilized as a technique to address anxiety in an effort to enhance relaxation,” said Dr. Heche.

Where do I find color noises?

Those interested in white, pink, or brown noises can use readily available items in their homes or workplaces (e.g., turning on a fan or switching to a television channel with static), or they can purchase sound machines or apps. Sound machines can play a mixture of soft, low pitch or loud, high-pitched sounds, such as television static or ocean waves, for hours at a time. 

You can also download noise apps from the Google Play Store and the App Store. Some apps may be free, while others may require a subscription. Also, several YouTube videos of color noises are available for free on the platform.

How loud should white noise be?

Sound is measured in decibels or dB. Any noise above 70 dB for an extended period can damage your hearing and lead to noise-induced hearing loss. A 2022 study suggests that adults can comfortably listen to white noise at 45 dB in an office space (about the same volume level of conversation). The volume may need to be adjusted in different noise conditions, although the noise should not exceed 70 dB for too long.