You will be quite familiar with the sound of white noise. It is a similar sound a radio makes when it cannot find a station. White noise is a constant sound which contains an even distribution of high and low frequencies. A good example of white noise is a waterfall, where water is hitting different surfaces (rocks etc) and moving at different speeds. The sound is very diverse, but when combined creates a consistent 'blanket' of sound. Similar sounds include <a href="https://www.soundofsleep.co.uk/what-is-pink-noise/" target="_blank" rel="noopener"><span style="text-decoration: underline; color: #58c8f4;">pink noise</span></a> and <span style="text-decoration: underline;"><span style="color: #58c8f4;"><a style="color: #58c8f4; text-decoration: underline;" href="https://www.soundofsleep.co.uk/what-is-brown-noise/" target="_blank" rel="noopener">brown noise</a></span></span>, however these have more emphasis on lower frequencies. White noise is an even balance of all frequencies, and this makes it a very effective noise blocker.

The use of white noise to cancel noises has been around for a long time. White noise machines are commonly used in large shared offices to mask conversations, phones ringing and clicking keyboards. It may seem counterintuitive to add a noise to an already noisy environment but it is very effective. The brain is able to ignore the white noise, but as it is still present, it cancels out any other noises. It effectively raises the volume of what the brain perceives as quiet.

Recently, white noise machines are being used as a sleep aid, and it is growing in popularity. As more and more people live in increasingly noisy and active towns and cities, disturbing noises are becoming more frequent, and as a result, so is poor sleep. Having white noise in playing in the background of the bedroom will raise the volume of what 'quiet' is to the brain, and cancel or dampen disrupting noises. The use of white noise as a sleep aid has been well demonstrated in several research papers.

The <span style="text-decoration: underline;"><span style="color: #58c8f4;"><a style="color: #58c8f4; text-decoration: underline;" href="https://www.soundofsleep.co.uk/product/lectrofan/">LectroFan</a></span></span> is a very popular white noise machine generator. Unlike other sound machines, the LectroFan produces a random non-looping white noise. Some sound machines simply repeat a track, and the brain will eventually recognise the end/start and patterns in the track, which can be more annoying that the sound you are trying to mask!