Most people are familiar with white noise, which sounds like a radio that hasn't been tuned properly. It is a constant sound that contains a range of frequencies. Brown noise is similar to this, however, brown noise has narrower range of frequencies. Compared to <a href="https://www.soundofsleep.co.uk/what-is-white-noise/">white noise</a> (and <a href="https://www.soundofsleep.co.uk/what-is-pink-noise/">pink noise</a>), brown noise contains more deeper frequencies, and doesn't contain the high frequency sounds. It can be described as 'softer' than white or pink noise. To compare it to familiar sounds, brown noise sound is comparable to sea surf on rocks, but it more consistent and constant rather than ebbing and flowing with waves.

Brown noise has attracted a lot of attention in recent years for its ability to help people sleep. Brown noise can help block out sounds like traffic, noisy neighbours and other disturbing sounds that disrupt sleep. Research has shown that people find brown noise relaxing, and so acts as a sleep aid from that perspective too. Brown noise is also commonly used for people suffering from tinnitus. The brown noise reduces the contrast between background noises and tinnitus, effectively masking the tinnitus.

Brown noise sound generators such as the <a href="https://www.soundofsleep.co.uk/product/lectrofan/">LectroFan</a> have gained popularity for promoting sleep. The LectroFan is particularly successful because the brown noise it produces is non-looping and random. This random sound is much better for promoting sleep than looping sounds. If a sound loops or isn't random, the brain will begin to recognise patterns which can become more distracting that the sound it is trying to mask!