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White noise is a mix of every audible frequency at the same amplitude.
Many sleepers fall asleep using white noise, a catchall term for static frequencies that are blended together to create soothing ambient sounds. Other colors of noise, such as pink, red, and blue, can also result in background sounds that are conducive to falling and remaining asleep. In addition to helping adults sleep better, white noise can be an effective sleep aid for children – infants and toddlers, in particular.
White noise machines – many of which can produce multiple noise colors – are widely available through online and brick-and-mortar retailers; price-points vary, but most cost $100 or less. A wide range of white noise apps for cell phones and other smart devices are widely available, as well. Bedroom fans may also be a good substitute for white noise machines, provided they are loud enough to block outside noise.
This guide will discuss the qualities and characteristics of different noise colors, as well as the benefits of using ambient noise as a sleep aid and some of the most common ways to produce white noise in a bedroom setting.
All sounds have a frequency, which indicates how many vibrations the sound wave produces each second; this is measured in hertz (hZ). The amplitude of a sound indicates the how large or small the sound waves are.
White noise, by definition, consists of different frequencies with the same amplitude. Just as the color white is a combination of every conceivable color, white noise consists of every audible frequency. This makes white noise effective at blocking all outside noises and sounds, regardless of their individual frequencies.
However, it’s important to note that the term ‘white noise’ is often used incorrectly. This is because pure white noise often sounds harsh to human ears due to its frequency range, which can be extremely high or extremely low. Many instances of white noise are actually ‘pink noise.’ Pink noise, like white noise, consists of varying frequencies, but the volume (in decibels, or dB) decreases whenever the frequency doubles. This results in a more balanced noise compared to the harsh contrasts of pure white noise.
Differences like these distinguish the different colors of noise. The table below lists definitions and properties of some of the most popular noise colors for sleeping.
|Color||Definition||Best Noise Color for…|
|White||All audible frequencies played at the same amplitude||Sleepers who prefer intense noise, as well as those who live in exceptionally loud neighborhoods|
|Pink||Volume decreases by 3 dB whenever the frequency doubles||Sleepers who prefer deep, bass-driven noises, such as thunderstorms|
|Brown/Red||Volume decreases by 6 dB whenever the frequency doubles||Sleepers who prefer deep, soothing noises, such as falling waves|
|Blue/Azure||Volume increases by 3 dB whenever the frequency doubles||Sleepers who prefer high-pitched noises, such as harsh wind|
|Violet||Volume increases by 6 dB whenever the frequency doubles||Sleepers who prefer exceptionally high-pitched noises, such as whistling kettles|
|Grey||Volume increases at 100 to 1,000 hZ, and decreases at 5,000 to 10,000 hZ||Sleepers who prefer to listen to static at a constant volume|
|Black||Silence; just as white noise is all frequencies, black silence consists of no frequencies||Sleepers who wish to fall asleep without noise as an aid|
White noise and other noise colors can take many forms. These include waves, wind, and other natural sounds, as well as humming fans, urban traffic, and crowd noise. The best white noise machines and apps sold today offer a mix of sound patterns and recordings that run the spectrum of noise colors.
Some notable advantages of using white noise and other noise colors include the following:
Sleep onset refers to the process of falling asleep, while sleep maintenance refers to one’s ability to remain asleep during the night. In many cases, white noise and other noise colors (pink noise in particular) have helped sleepers improve their sleep onset and their sleep maintenance. White noise machines and apps with sleep timers – especially those that gradually decrease the volume – can be quite effective. Alternatively, these machines can usually be programmed to run until morning, which accommodates sleepers who prefer to listen to ambient noise all night.
As we’ve discussed above, white noise contains every audible frequency; this allows it to block all outside noises. Comparatively, recorded music can block outside noises that match its frequency, but it will be less effective at blocking sounds with different frequencies. The same is true for other recordings and sound patterns with a limited frequency range.
In addition to helping adults sleep better, white noise can have a calming effect on newborns and infants leading up to naps and bedtime. Ambient noise can also be effective as a relaxant during feeding sessions. Most parents find that white noise therapy combined with effective swaddling will yield the best sleep for babies. As they grow older, young children with sleep problems – or those who are afraid of the dark – may also benefit from listening to white noise when they go to bed.
However, the effects of white noise on newborns and infants have not been studied extensively. A few studies have noted that white noise can reduce wakefulness and fussiness in babies, but parents are still advised to limit their child’s exposure to white noise – particularly at high volumes.
Anyone who frequently travels can attest to the difficulty of falling asleep on planes, trains, and other forms of public transportation. White noise can be a useful sleep aid and noise-blocker in these loud, crowded settings. Many white noise machines sold today come with headphone jacks and are small enough to fit in a carry-on bag. If luggage space is limited, travelers can download a white noise app onto their smartphone instead.
Poor sleep can exacerbate symptoms for people with attention-deficit/hyperactivity disorder (ADHD) and other disorders that affect focusing abilities. White noise therapy may be used to increase cognitive function and sharpen concentration for these individuals. In some cases, listening to white noise during the day – especially during work – has been shown to help, as well.
Devices known as a white noise machine, or sound machines, are the most common method of experiencing white noise therapy. Contrary to the name, many of these devices produce different colors of noise; pink and brown/red are the most common options, but select machines can generate many colors on the noise spectrum. Additionally, many come equipped with a collection of natural and ambient sounds. White noise machines use sophisticated looping techniques to sustain a 15- or 20-minute recording for an hour or longer.
Additional white noise machine features often depend on price-point. More expensive models may include sleep and napping timers, AM/FM radio with presets, headphone jacks, alarms, and sound mixing capabilities. Lower-priced models typically do not include these features. In terms of cost, white noise machines may cost anywhere from less than $20 to more than $200. For more information about purchasing white noise machines, please visit our Best White Noise Machines – Top Picks and Buyer’s Guide.
In addition to white noise machines, the following products can be used to block outside sounds.