Noises Used For Improving Sleep

Many types of noise can help people sleep by relaxing them and allowing them to drift off itno blissful slumber.

Written by:


, Sleep Researcher
Last Updated: Sun, October 6, 2019
Fact checked by:

Marko Jevtic

, Sleep Specialist

There are many types of noise that help people sleep, and many sleepers tend to use these noises for drifting off into blissful slumber. Most individuals use white noise – a term used to describe all static frequencies put together to make relaxing ambient sounds. Other types of noises or different colors of noises are pink, blue, brown and red, and they can also help with falling and remaining asleep.  

The noises are usually associated with colors, similar to light. White light looks white because it is a combination of all the colors of the rainbow equally represented. In the same manner, white noise is a combination of similarly represented frequencies, whether the lower or higher ones. Also, there are other colors of noise, such as red noise, pink noise, blue noise, brown noise, and grey noise and scientists are just beginning to explore their functions.


What is White Noise?

White noise is similar to white light. It is a combination of all the sound frequencies that we can hear, just like all prism colors are combined in white light. It has a range of different frequencies with the same amplitude, which is measured in Hertz. Frequencies indicate the number of vibrations produced by the sound wave per second. White noise sounds like a waterfall and its volume does not change with frequency changes. Therefore it is very efficient in masking noises from our environment and alleviating tinnitus troubles.

According to research, it can also help induce sleep. In healthcare, it is used to treat increased sensitivity to environmental sounds. However, the sound of pure white noise is often harsh for our ears because its frequency range can be very high or very low. It is often mistaken for pink noise, which also has a range of frequencies, but its volume decreases with the frequency increase. Therefore pink noise sounds more balanced and susceptible to the human ear.

White noise has been studied widely, with the outcomes indicating its ability to help us fall asleep easier or calm down patients in hospitals by blocking background noises. For example, a fan in one room can block the sounds from the other room, helping you to calm down and fall asleep, which gives the noise a fan produces the character of white noise. It is similar to the murmur of a large number of people where our brain cannot differentiate any particular voice, but a buzz of sounds, which is also considered to be white noise. The fact that the white noise can cut through environmental sounds has qualified it for use in everyday life, for example in sirens of emergency vehicles.


What is Pink Noise?

White noise and pink noise are similar in the sense that we can hear them equally, but there is a difference between them when it comes to frequencies. It refers to the fact that both of them cover the range of 20 hertz to 20,000 hertz. However, they differ in the way their signal is distributed. White noise power per hertz is even throughout all frequencies, whereas pink noise power per hertz decreases as the frequency increases, resulting in more power in lower frequencies than in higher ones.

Pink noise is a combination of several natural sounds, such as thunder, ocean waves crashing, a huge waterfall, steady rain falling or the wind rushing through the leaves, so it is optimized for our listening perception, whereas white noise might sound thin or harsh. Its pattern is present in our daily heartbeat rhythm or traffic flow. However, what is pleasant for our ears is a singular sensation, so some scientists tend to advocate the idea that whatever we find relaxing will work for us. In that respect, some people find techno music relaxing with its steady beat, but for others, it might be annoying. The concept is that both white and pink noises benefit our relaxation by eliminating background sounds, but some people find pink noises deeper and gentler, helping them to improve their focus, sleep better and cure headaches. Some noises that don’t bother us during the day as they are masked by other daily sounds, such as faucet dripping, can become our nightmare during the night, as the surrounding silence enhances them.

With age, our deep sleep becomes critical, thus causing the whole range of side effects, such as the loss of concentration and memory. This is where the pink noise can help according to some researches who suggest listening to soothing sounds – a mix of high and low frequencies that are balanced, as a solution. As we mentioned above, the volume of higher frequencies in pink noise is milder, meaning that – the higher the frequency, the lower the sound, so the sounds seem equally strong and the listening experience relaxing. Thus, the sounds do not seem as high as in white noise. However, the research of pink noise is not as extensive as in the case of white noise. Some studies indicate that constant pink noise helps by reducing brain wave complexity. It is also said to induce better sleep in the sense of its quality and duration. What is interesting is that in specific studies some subjects exposed to pink noise experienced longer deep sleep and better quality napping than the subjects exposed to no noise.

Also, in another study, subjects were shown several word pairs before being exposed to pink sound during the deep sleep phase, whereas another group was not exposed to any sound. The group of subjects exposed to pink sounds was able to remember twice as many word pairs as compared to the no sounds group the following day, displaying much better memory. The main reason for this is considered to be the fact that the frequency of pink noise sounds was synchronized with the subjects’ brain waves. However, after a clinical trial on how different color sounds affect tinnitus, it has been concluded that pink noise did not have any effect on patients with tinnitus. Two-thirds of patients exposed to different color noises preferred white noise, and the rest of them chose red noise, while pink noise was not the preferred choice for any of them. Such a result indicated the necessity to tailor the treatment according to the needs of each individual patient.

One must always bear in mind that we all respond to noises differently, so the advice of the researcher mentioned above is that we should all find what works for us best. Pink noise has its application in everyday life such as for testing loudspeakers. It is also applied in business more and more, since it can mask the low-frequency background sounds, which help to enhance the concentration of employees, thus increasing their productivity.

Finally, as we noted, the research into the benefits of pink noise is still limited. More studies are required to definitely conclude how the effects of pink noise are different from white noise and other noise colors.


Other Types of Noises

Apart from white and pink, there are many other colors of noise. Among those colors are brown, blue, violet, and gray.

Brown noise got its name after a botanist named Robert Brown. He discovered the Brownian motion (random particle motion). The noise is also known as Brownian noisy to its random change in sound signal. It has a spectral density that is oppositely proportional to the frequency. This means that the power decreases while the frequency increases, and because of that it makes a lot of energy while having a low-frequency. To us, brown noise is actually very similar to white noise. The difference is that brown noise is much deeper, with a sound that has a low roar, and it contains all the humanly audible frequencies that boost the lower frequency range, which can be very useful for enhancing sound privacy, blocking out annoying noises and for treating hyperacusis and tinnitus.

Blue or azure noise has low frequency components without any concentrated spikes in energy. It is sometimes regarded as high-frequency white noise, but its spectral density is proportional to its frequency. Each successive octave increases by three decibels, which is why the power increases along with the frequency. This blue noise is biased toward higher frequencies, so it results in a high-pitched sound without any base. The noise is used for dithering – a process in which you add noise to a track in order to smooth out the sound and minimize the distortions.

Violet or purple noise is defined with the power increase with each increased octave in the frequency. Because it is the result of a white noise signal differentiation, the noise is also known as differentiated white noise.

Grey noise is random white noise that is the result of a loudness curve that happens in a range of frequencies. At all frequencies, the listener gets an equally loud perception of the sound. That is the opposite of the standard white noise that has an equal strength on all frequencies but does not make an equally loud sound on all of them.


How to Generate Environmental Noise and Block Sounds?

White noise or sound machines are the ones used for generating different colors of noise. Do not be fooled by the name, it does not produce white noise only. These machines can make all the different colors of noise, with white, pink, blue, brown, violet and grey being the most popular options. And many of these machines shave a collection of natural and ambient sounds that come with them.

Apart from white noise machines, you can find a variety of white noise apps for smartphones that vary with the options of sound selection and quality. Some have extensive noise and natural sound selections, but many more have a limited selection. This depends on how much the app costs.

Electric and ceiling fans can also be used as white noise machines. They produce a soothing whirr, very similar to white noise, and if the whirring is loud enough, you can block outside noise to a noticeable extent.

Noise-cancelling headphones are very useful for sleepers that do not like hearing white noise or any sound during their sleep. Headphone models that do not penetrate the ear but still cover it are the best choice. Similar to headphones, you can get earplugs that block outside noise. They mold to the contours of the user’s ear and effectively block all sounds. However, contrary to headphones, long-term use is not recommended for earplugs because they can cause many problems like earwax buildup and tinnitus.


Benefits of Falling Asleep to Ambient Noise

Each color of noise has its benefits that fit the needs of different sleepers. White noise is best for sleepers who like intense noise and live in very loud neighborhoods, or expect to be sleeping in loud environments. Pink noise is for individuals that like deep and bass-driven sounds, similar to thunderstorms. Brown noise is ideal for those who love hearing soothing noises, similar to a waterfall or falling waves. Blue noise is helpful for people who like high-pitched noises, like those you can hear from harsh wind. Violet noise is also for those who like high-pitched sounds, but they prefer noises similar to whistling kettles. Grey noise fits people who love hearing static at a constant volume.

As we mentioned before, there are many benefits to using white noise and other noise colors. Here are certain general benefits environmental noise can offer you.

Effective Noise Blocking

These noises have audible frequencies that block all outside noises. Music can also block noises if it matches the frequency, but it has been proven to be less effective to block different frequencies. It does an excellent job at masking the sound of office machines, loud congestion area, co-workers, roommates, and it can create a more productive environment.

Helpful For Infants

It is a good sleep aid for adults, but it can also help babies. The noises have proven to have a calming effect on infants and newborns before their bedtime. They also have a relaxing effect during meals and feeding. It also helps older children that have sleep problems.

Improves Concentration

Adults or children with attention-deficit/hyperactivity disorder (ADHD), or even other disorders, have poor sleep problems. Attention deficit hyperactive disorder (ADHD) usually happens to a child that is about to go into puberty, and it can continue to last in adulthood too.  The symptoms of these disorders can severely impact sleep. Children with ADHD have sleep issues and heightened daytime sleepiness. Among the symptoms are also difficulty waking up early, bedtime anxiety, occasional parasomnias, and sleep onset and/or maintenance problems. Noise therapy, especially white noise therapy, is often used to help increase cognitive function and concentration for individuals with these problems. Additionally, listening to white noise during the day – during work or studying, has positive effects on concentration too.

Improved Sleep Onset and Maintenance

Sleep onset is the process in which you fall asleep, and sleep maintenance is the ability to be asleep. Noise, in particular, white and pink, have proven to be helpful for falling asleep, and for improving sleep maintenance and sleep onset. There are white noise machines and apps that have sleep timers that are very effective for these issues. These machines can be programmed to last until morning, so you will be able to listen to ambient noise during the whole night.

Handy Travel Help

Individuals that travel a lot have many difficulties with falling asleep while traveling with trains, planes, buses or any other form of transportation. In these cases, white noise serves as a useful aid for sleeping and for blocking noise in any loud setting. Many white noise machines that are available on the market today have a headphone jack.


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Iva is an art historian and an art lover who always had a passion for writing and sleep! When she is not researching and testing new mattresses on the market, you can find her binge-watching TV shows, eating tons of junk food or playing with her dog Bart.

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