People can describe the power of a noise signal using color, in a similar way to how people may describe light on a spectrum. Two colors of noise that exist on this spectrum are pink and white noise. Research suggests that these colors may have many potential applications, such as aiding sleep.
A person can determine the color of noise by the energy of the sound signal, with the color referring to how the signal distributes energy over various frequencies. Pink and white noise both encompass all audible frequencies but differ in how they distribute energy across these frequencies.
Some researchers believe that pink and white noise might offer potential benefits, including better sleep and improved productivity. However, more research is necessary to investigate the effects of these colors of noise and how people can use them.
In this article, we look at pink and white noise in more detail, including their differences and potential uses.
Definitions
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Sonic hues, also known as the noise spectrum or colors of noise, describes the practice of naming different noises after colors. The color of the noise relates to the power spectrum of a noise signal, or the frequencies of the noise.
The practice of naming noises after colors originated with white noise. Researchers chose this system to classify noise as it mirrors how they measure light on the electromagnetic spectrum. For example, just as white light includes all visible light, white noise includes all audible frequencies.
Most colors of noise take their name from a color of light with similar spectra. Other colors on the noise spectrum include red, purple, blue, and gray.
Differences
White noise refers to noise that contains all of the frequencies across the audible sound spectrum, which are those in the range of 20–20,000 Hertz (Hz). There is an equal distribution of all frequencies within white noise. Some people may refer to white noise as broadband or wideband noise because it encompasses multiple bands of sound.
Examples of white noise include:
- television or radio static
- whirring fans or the sound of ventilation systems
- wind
- heavy rain
- waterfalls
Pink noise is similar to white noise in that it is also a broadband noise, containing all frequencies between 20 Hz and 20,000 Hz. However, pink noise is deeper than white noise due to a reduction in power at higher frequencies and an increase in power at lower frequencies.
Examples of pink noise include:
- heartbeats
- waves hitting the shore
- steady rainfall
- leaves rustling
Potential uses
The benefits of white noise and pink noise have been a popular topic of research. Some possible benefits include:
White noise potential uses
Researchers have investigated the potential benefits of white noise more than those of the other noise colors. One major topic of research is the use of white noise in improving the quality of sleep.
In a small 2021 study, using a white noise device in the bedroom significantly improved the participants’ sleep. Similarly, a small 2017 study found that broadband noise reduced the time it took participants to get to sleep by 38% compared with normal environmental noise. The researchers suggest that broadband noise may help reduce insomnia symptoms in some individuals.
However, a 2021 systematic review notes that the current quality of evidence regarding the use of white noise as a sleep aid is low and that additional research is necessary before promoting its use.
Other possible benefits of white noise include:
- potential symptom improvement in children with attention deficit hyperactivity disorder (ADHD)
- enhancement of new word learning and recall
- improvement in auditory working memory performance
- decreased crying duration and increased sleeping duration in babies with colic
Pink noise potential uses
Researchers have also investigated pink noise to see whether it might improve sleep. A small 2017 study found that participants who listened to short bursts of pink noise on a loop during sleep exhibited improvements in memory and recall during a cognitive task. However, the authors note that pink noise did not change the participants’ self-reported sleep quality, mood, or alertness.
A similar 2020 study found that pink noise helped participants fall asleep and achieve deep sleep faster. A small 2020 study indicates that pink noise may improve work efficiency, continuous performance, and working memory.
However, it is important to note that many of these studies included a small number of participants. Larger studies are necessary to confirm the clinical benefits of pink noise.
How to use
A person can try using white and pink noise to improve their sleep.
For example, a person may use a white or pink noise machine to produce a steady background noise in the bedroom. Although there is a scarcity of research, leading theories suggest that these colors of noise may aid sleep by providing a calming environment, forming part of a bedtime routine, or masking loud and distracting noises. These machines are available commercially.
A person can also download white and pink noise apps on their mobile phone. Similar to machines, these apps are capable of playing white or pink noise, which a person can use to try to improve their sleep. People can search for these apps via the application store on their phone.
Other sleep tips
White noise and pink noise have shown some benefits in research, but it is important to note that not everyone will react in the same way to these noises.
It is much better to practice good sleep hygiene, which refers to sleep habits that may have positive effects on sleep quality. The Centers for Disease Control and Prevention (CDC) advise that adults should aim for 7 or more hours of sleep per night and recommend:
- going to sleep and waking up at the same time each day, even on weekends
- ensuring that the bedroom is a suitable sleeping environment
- placing distracting electronic devices out of reach and sight when in bed
- avoiding large meals, caffeine, and alcohol close to bedtime
- being physically active during the day
Summary
Pink noise and white noise refer to varying frequencies of noise. Similar to how people can determine the color of light, people can use color to describe the frequency of noise.
Both white noise and pink noise encompass all frequencies of noise that are audible to the human ear. However, white noise contains all frequencies with equal distribution, whereas pink noise has more power at lower frequencies and less at higher frequencies, making it deeper.
Examples of white noise include TV, radio static, and ventilation systems. Examples of pink noise include steady rainfall, waves, and rustling leaves.
Research indicates that both white noise and pink noise may have beneficial effects on sleep. Some evidence also suggests that white noise may be helpful for children with ADHD, while pink noise may boost working memory and recall. However, more research is still necessary to determine the effects and uses of these noises.
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