White noise is a special type of sound which masks sounds in the background.
White noise is a noise whose amplitude is constant throughout the audible frequency range. White noise contains every frequency within the range of human hearing (generally from 20 Hz to 20 kHz) in equal amounts. White noise is like white light which contains all the colours (frequencies) combined together. White noise, like white light, consists of all frequencies combined together.
There are a lot of other colours of noise as well, for example, brown, grey, pink, violet, red etc. Pink noise, like white noise, is considered to be a potential sleep aid. These various colours represent a specific spectral density, having different applications in acoustics, physics and engineering.
A theory of white noise has its origins in mathematics and engineering, but today it has applications in such fields as acoustics, electronics, computer programming and economics as well. White noise is often used for promotion of healthy sleep – it helps to drown out sounds which awake during sleep or interfere falling asleep. Adding more noise in a bedroom may seem weird, but actually white noise blends external sounds into overall background noise, so the brain pays less attention and continues to sleep. It should be mentioned, that it depends on the context of the sound, not on the volume of the sound. That is why some people can fall asleep in a noisy nightclub, but some people wake up from a distant barking dog.
Sometimes white noise is described as any type of constant and unchanging noise in the background. White noise has become a colloquial term for a diverse range of sounds, for example, sounds of nature (rain, waves, jungle etc.), sounds of machinery (washing machine, air conditioning units, heat pump etc.), ambient sound (crowd noise, aircraft interior, crackling bonfire etc.). A lot of people prefer to listen to these types of sounds when they try to fall asleep, rather than pure white noise.
These days you can purchase a variety of special devices which provide white noise, but you do not have to spend any money if you want to try white noise as a sleep solution, because there are a lot of other options which do not cost a penny. One of options is old radio or anything else with FM tuner, where you can dial in between stations or break the antenna, obtaining an approximation of pink noise. It is not recommended to use TV as a source of white noise, because the flickering light can harm the quality of sleep. Also fun is a great option for sound masking. Nowadays everyone can download free MP3s of white noise on many different sources. Everything you need is something to play the MP3s, for example, MP3 player, mobile phone or computer. Today one of the easiest ways to try white noise is with smartphone, because there are countless free and paid applications which are designed for improvement of sleep.