| White noise is: A sound containing a blend of all the | | | | recordings usually on CD format. |
| audible frequencies distributed equally over the range | | | | The mechanical devices produce a sound very close |
| of the frequency band. White noise is analogous to | | | | to that of a fan. The Sleepmate by Marpac is this |
| white light which contains all the colors of the | | | | type of device and has been around for a long time. |
| rainbow together. The term "white noise" as used in | | | | This is the most popular type of white noise machine; |
| this article will be applied a little looser to include a | | | | probably because it produces a sound that we are all |
| host of sounds (waterfall, rain and brook as | | | | familiar with and don't find unpleasant. One drawback |
| examples) used for blocking out unwanted sounds. | | | | of the mechanical units is that they are limited in |
| Because white noise contains most sound | | | | volume. Since they produce the sound mechanically, it |
| frequencies, it is commonly used to mask other | | | | isn't possible to simply turn up the volume. |
| sounds. If you are in a hotel and voices from the | | | | White noise is commonly generated with a digital or |
| room next-door are leaking into your room, you | | | | electronic sound synthesizing device. Sound designers, |
| might turn on a fan to drown out the voices. The fan | | | | with some processing and filtering, can create a |
| produces a good approximation of white noise. How | | | | multitude of effects such as wind, rain, waterfall or |
| does this "white" sound work and why does it mask | | | | surf. The main consideration when choosing a digital |
| out other noise? | | | | device is if the device loops a recorded clip of sound |
| Here is one way to think about it. Let's say two | | | | or synthesizes its own sound. By looping we refer to |
| people are talking at the same time. Your brain can | | | | a few seconds of sound that is digitally recorded and |
| normally pick out one of the two voices and actually | | | | played over and over. They try to match up the end |
| listen to it and understand it. If three people are | | | | with the beginning but if you listen carefully you can |
| talking simultaneously, your brain can probably still pick | | | | detect where the segment begins - this is irritating to |
| out one voice. However, if 1,000 people are talking | | | | some people. The better digital sound devices actually |
| simultaneously, there is no way that your brain can | | | | synthesize the sound instead of playing a recording, |
| pick out one voice. It turns out that 1,000 people | | | | therefore no looping. |
| talking together sounds a lot like white noise. So | | | | Compact discs are a popular and inexpensive way |
| when you turn on a fan to create white noise, you | | | | (not counting the cost of a stereo system) to bring |
| are essentially creating a source of 1,000 voices. The | | | | white noise into your home or office. You can get |
| voice next-door makes it 1,001 voices, and your brain | | | | almost any sound imaginable but the most commonly |
| can't pick it out anymore. One thing to keep in mind | | | | used are nature sounds like rain, thunder or babbling |
| when using white noise is that more is not always | | | | brooks and nature sounds overlaid with soft music. |
| better - it is usually best to use just enough to help | | | | The advantages of CDs are a high quality sound and |
| mask the offending noise, not completely overwhelm | | | | low cost. The disadvantage is that, if you are using |
| it. | | | | the sound to help you sleep, the interruption when |
| There are three sources of white noise that are | | | | changing tracks or cycling will often times wake you |
| commonly used to help mask out annoying sounds: | | | | up. Generally the best uses for CDs are for office |
| mechanically generated, electronically generated and | | | | privacy, meditation or just relaxing. |