I’ve you ever had trouble sleeping chances are that someone has recommended that you try white noise as it helps fade others noises into the background allowing you to sleep with ease.
They probably didn’t suggest that you use brown noise and pink noise however these are also common noise colors.
You may be wondering what the color of noise means and what the difference is between white, brown and pink noise.
Sound is made up of a combination of two key things:
Noise colors refer to where on the power spectrum density scale a noise signal sits (power spectral density is Amplitude2/Hz).
When the power spectrum is shown as an image it reveals different colors for different noise types as shown below:
White noise is noise which has a flat spectral density.
The graph above shows that the white noise covers a broad range of frequencies yet these are emitted at a constant power spectral density (the power spectral density does not change as it does with other colours of noise).
White noise is sound which is made up of a lot of different sounds which all occur at a frequency which the human ear can hear (between frequencies of 20 - 20,000 hz). When these sounds are combined at similar volume levels it creates a calming white noise sound.
White noise is very similar to white light. If you’ve ever done the science experiment of splitting light with a glass pyramid you will be familiar with the concept of white light being made of a combination of all different light colours combined together. White noise is exactly the same!
Click below to hear exactly what white noise sounds like:
White noise is brilliant for anyone who is having trouble sleeping because background noise blends into it. White noise also helps deal with ringing noises in your ear, it is also great for helping your baby to sleep making it a brilliant and cheap alternative to soundproofing a nursery.
A few sources of white noise that can be found in the world around us (without having to download an app or play a YouTube video) include; waterfalls, rain, the murmur of a crowd, road-noise, the hum of a car engine, a hoover, a fan or even TV static.
Pink noise is much the same as white noise except the top-level frequencies are lower, it consists of a blend of low and high-frequency noises which give it a higher pitch than brown noise but a lower pitch than white noise.
The graph above shows that unlike white noise it does not maintain intensity regardless of frequency. Instead, it loses intensity as frequency increases.
Click below to hear what pink noise sounds like:
Pink noise can help aid concentration and it can be good for improving your sleep.
A study revealed that pink noise can help regulate your brain waves, giving you a better quality sleep. Another study also revealed that pink noise can enhance deep sleep for people with mild cognitive impairment as well as people who are at risk of developing Alzheimer’s disease - so it clearly has plenty of benefits!
Brown noise doesn’t actually get its name from the colour shown on the power spectral density graph (it's actually red!) its name comes from the botanist Robert Brown who discovered it.
It’s name also relates to the way it functions. The word Brownian means leaping which is appropriate because brownian noise changes its signal randomly from one moment to the next.
Where white noise maintains its power per hertz at all frequencies brown noise loses power as its frequency increases (see the red color in the graph at the top of the page) at a faster rate than pink noise as you can see in the graph below:
This means that at low frequencies brown noise has much more power.
Brown noise has lower top frequency levels than pink poise giving it a deeper sound.
Click below to hear exactly what brown noise sounds like:
To the human ear brown noise sounds much like white noise just deeper. Examples of brown noise in the real world include things like a powerful waterfall.
Brown noise can be used as an alternative to white noise for sleeping, it is also commonly used to create a comfortable environment in schools or home where people may be feeling anxious.