Technology with the ability to nullify sound(s) by means of a computer listening to the undesirable sound(s), designing and then broadcasting the 'antisound', all in real time; but with a slight delay on the sound broadcasting, so as to sync up with the undesirable sound(s). Antisound itself is a single, or collection of sounds whose waveform is inverted with respect to the waveform of the undesirable sound. Opposite sound waveforms cancel each other out through the process of destructive interference.
Ideally the antisound is broadcast from a location in close proximity to where the undesirable sound originates. Otherwise, unless the entire machine or environment (or a good portion thereof) can function as an antisound creating diaphragm, some locations in the environment will be silent while others are not due to how sound propagates. When some level of residual sound is desirable (sounds such as to alerts regarding the nearby operation of dangerous machines), the antisound technology is programmed to only cancel out most of the sounds and cut down on the decibel level.
Text by John Edds
Initially published on 22 May 2006.