White Noise Sound
A white noise sound
occurs when many sound waves are played simultaneously at nearly all frequencies. Since a White Noise Sound
has many different sound waves occurring at the same time along with the noise you want to cancel, the peaks of some sound waves are going to line up with troughs of other sound waves thereby cancelling both sounds out in a process known as destructive interference. Many of the sound waves are not perfectly aligned, so a lot of sound remains while some has been cancelled out making the conversion occurring in the next cubicle or apartment difficult to understand. A white noise sound is technically any sound containing all frequencies of the spectrum but more practically it is a sound that can be used to mask, cover, obscure or even cancel out other annoying noises. It is worth noting that the closer a white noise sound is to the pure definition of white noise, the more effective it will be at cancelling out other sounds. The downside of pure white noise is that it is not pleasant for most people to listen to, in that a pure white noise sounds a lot like the static from a radio that is off station. Therefore what the makers of white noise sounds shoot for is an approximation of white noise that is close enough to be effective yet has qualities that make it reasonably pleasant. A white noise sound or a reasonable approximation can be produced by many different devices, from a fan, air conditioner or vacuum to specially made white noise sound machines specifically engineered to create a sound for the purpose of helping to block out distracting noise.
The white noise sound machines come in many brands, each having many models resulting in a bewildering array of machines with varying degrees of quality, features and price. We will try to cut through some of the clutter to find the white noise sound that will be the best fit for your needs.
Have you ever noticed how easily (sometimes) a baby can fall asleep in a car with the engine running but when you pull into the drive and turn off the engine, the baby wakes right up? You are witnessing the effect that a white noise sound can have on an unbiased and impartial and natural judge (the baby). The baby hasn't been subjected to advertising; the baby hasn't been conditioned to like or dislike certain sounds; the baby hasn't been convinced that a particular sound is better. The baby is about as close as we can get to a true impartial judge on the effectiveness of a white noise sound. Unfortunately, I don't have the time and resources to operate a side by side comparison of the various white noise sound machines using babies as the test audience. But we can draw on our experiences with babies falling asleep to draw some conclusions about the likely effectiveness of some types of sound machines.
We noticed babies seem to easily fall asleep with a soft mechanical sound. In the example above, the car was not a loud race car without a muffler, it was a regular passenger car with a muffled sound. Taking our clue from the baby, the only sound machine that uses an actual motor to make a soft fan like white noise sound is the Sleep Mate 980-A
There are a couple drawbacks to the Sleepmate, one is that it does not go to a loud volume, the other is that it only makes one kind of sound, the fan like mechanical sound mentioned above. So if you want more variety in the sounds produced and the option of having a louder volume, the Sound Oasis S-650
would be our recommendation for a quality white noise sound with lots of variety and a good speaker capable of high volume.