White noise is the fuzzy, static sound heard when there’s no signal on your television or radio. A sound you’d probably try to get rid of as quickly as possible.
So why is there a whole industry built around white noise machines? And can it really help you relax, fall sleep or study better?
To understand why people would want to listen to it, let’s first take a look at exactly what white noise is.
What is white noise exactly?
The term ‘white noise’ is actually used in several different contexts. For the purpose of this article though, I’ll only be looking into white noise in terms of audio – the most common context.
It’s helpful to look at the name itself to start with. White noise gets its name from ‘white light’. In simple terms, white light is all colors, or frequencies of color, combined together.
In a similar way, white noise is so called because it’s a combination of all the different frequencies of sound you’re able to hear.
The white noise we talk about usually isn’t every possible sound put together though. White noise is the signal, or frequency, created when all the different frequencies of audible sound that the human ear and brain can perceive are put together at a similar level.
The sound of white noise we hear as humans therefore is the sound of all the frequencies between 20 and 20,000 HZ. So we’re literally hearing around 20,000 different tones of sound all at the same time. No wonder it sounds messy!
If you think about it this way – imagine you’re sitting in a quiet restaurant. You’ll be able to pick out the individual voices of your companions, and perhaps those on other tables.
But now imagine you’re in a sports stadium waiting for the game to start – there may be thousands of people all talking at the same time, and it will sound like a blurred roar.
White noise has a similar effect – you’re listening to so many different tones all at the same time, it blurs into that ‘hissing’ or ‘shushing’ sound.
This is also why the sound of rain, wind, waterfalls or oceans can be found on white noise machines – there are so many different tones created by those forces of nature, that it becomes similar to white noise found on a television, radio or created in a studio.
The graph below shows the results of our poll into white noise. Interestingly, many readers do listen to white noise for various different reasons. However, 308 out of 854 people said they’ve never listened to it intentionally.
What is pink noise?
The simple explanation is that pink noise is a variation of white noise which sounds deeper, and with less of a high-pitched hissing.
The more complex explanation revolves around why white noise sounds high-pitched in the first place.
The reason is because each octave contains twice as many frequencies as the one below it. So for example between 100hz and 200hz there are 100 distinct frequencies.
But between 200 and 400 hz there are 200 frequencies. So by the time you get to 20,000hz, there are many more frequencies than there were at the lower end of the range.
When pink noise is created in a sound lab, the sound engineers will usually reduce the volume of each successive octave to compensate for the extra frequencies.
This balances the sound out by giving more ‘energy’ to the lower octaves, and gives it a ‘deeper’ sound overall than white noise.
What is brown noise?
Brown noise, sometimes called Brownian noise, sounds even deeper than pink noise, and considerably deeper than white noise. It often sounds like rushing water – like a waterfall.
It’s not named after the color brown, but after Robert Brown, who discovered Brownian motion. This is because the signal is produced by the random pattern of particle movements.
Brown noise can be produced, but not the same way as white noise or pink noise, and is much harder to create. It involves the sound engineers using each sample to create the next one with an element of randomness introduced to the previous sample.
Can brown noise make you lose bowel control?
Despite being an amusing urban legend, brown noise shouldn’t make you lose control of your bowels! The legendary ‘brown note’ is supposedly an infrasound frequency that makes people lose control.
However, experiments have been done by scientists, the military and in documentaries showing that there is no ‘one frequency’ that works on all people.
Yes, some people may react badly to the resonance of certain frequencies, but there is no one sound you can create to make masses of people all run for the toilet.
What’s white noise useful for?
Because white noise contains all audible frequencies, its most common use is to mask unwanted sounds. This can be very useful in certain circumstances.
Most people find that they easily get used to the noise and don’t find it disturbing. It literally fades into the background, and takes other external sounds with it.
So who might find it useful, and in which situations?
1. Helps you sleep by blocking out disturbing sounds
For light sleepers who are easily kept awake by external sounds, listening to white, pink or brown noise at night can help block out these sounds.
So if you have trouble falling asleep because of the sound of traffic, or a television someone is listening to, then white noise can stop you hearing the sound in the first place.
White noise contains all audible frequencies, so your ears are overloaded with sound and are not able to pick out the other sounds that would normally disturb you.
You need to have the white noise loud enough for this to work completely though. Otherwise it will help mask other sounds, but not hide them altogether.
The other theory behind why white noise helps you sleep is that your brain is incredibly active and loves stimulation. So any noise in the night will engage your brain.
Having a constant white noise will therefore satisfy your brain’s need for stimulation and prevent it from getting over-excited when it hears sudden noise in the night.
You can also experiment with different kinds of white noise. If the sound keeping you awake is a deep traffic noise, then maybe try pink or brown noise instead as they have more strength at the lower frequencies.
And if ‘pure’ white noise is just not relaxing enough, you can always try listening to rainfall, oceans, wind or other white noise sounds from nature.
You can even buy purpose built white noise machines which have the option to play pure white noise, or different sounds from nature.
2. Helps babies to relax and sleep better
Babies are easily kept awake or woken up by sudden sounds. White noise can help to drown out these sounds and keep them sleeping for longer.
Babies are already accustomed to listening to constant noise – the womb isn’t a quiet place, and white noise is similar to the sound of blood rushing by in the womb.
So babies often find white noise, or nature sounds, relaxing – during the day or at night.
3. Can help you concentrate – for a while
While writing this article, I’ve been listening to pink noise constantly. I can hear the sound of traffic quite loudly from where I work, but the pink noise completely drowns it out.
This stops me from being distracted by changes in the volume of traffic, loud motorbikes, trucks and beeping horns.
I find it’s very effective and I’m so used to the sound now that as soon as I put it on I feel focused, and it fades nicely into the background. I’m always very surprised how loud the traffic is when I turn off the pink noise again.
It’s also sometimes used by people who work in other kinds of noisy environments, such as manufacturing or where there’s a drone of technological devices.
However, despite my own positive experience with white noise, some studies have shown that listening to white noise constantly to aid concentration can have a negative impact on your performance, stress levels and memory.
Other studies have been done to see if white noise can improve the concentration of children with attention difficulties. It appears that it does in some situations, but also decreases the performance of children who don’t have attention problems.
Overall it seems this is still a developing area. My personal experience is that listening to white noise is better than listening to the drone of traffic. But perhaps after a few more days or weeks, it will start to irritate me.
4. Helps mask tinnitus
I can also personally attest to the theory that white noise helps ease tinnitus. Having had chemotherapy for cancer treatment 2 years ago, I now have tinnitus as a permanent side effect of the Cisplatin drug.
Especially bad at night time, or if I’m tired, ill or stressed, I find that white noise in any form – pure or sounds of nature – helps to block out the ringing I hear from tinnitus.
This then makes it easier for me to relax and fall asleep, as I’m not being annoyed by the changing of tones that my tinnitus has.
5. Promotes relaxation
Whilst pure white noise like that heard on your television isn’t usually thought of as relaxing, nature sounds often are. There are many soundtracks created either by recording sounds from nature or synthesizing them – and for good reason.
People find the sound of oceans, rivers, forests, waterfalls and rain – to name just a few – calming, relaxing and peaceful. It may not be for everyone, but most people will state that one of the joys of being in nature is listening to the sounds.
So the next time you are feeling stressed, why not have a listen to the sound of an ocean or waterfall and see if it helps you unwind?
Where can you find the best white noise?
There are many different options for listening to white noise. The easiest way is to just turn your television to an un-tuned channel, or turn your radio to a frequency with no signal.
You can also get white noise machines which are designed to play white noise or nature sounds. And there are interactive websites that create it for free.
To find out more about these options, have a read of my article discussing the best sources of white noise.