17. Noise Generators

The noise generator is another common synthesis module classified as a generator. As the name indicates, the noise generator outputs noise. While oscillators output frequencies in discrete spectra (in other words, they generate the specific frequencies that make up a waveform), noise generators output all frequencies distributed randomly through the entire audible spectrum. In this context noise does not mean "undesirable racket" but rather a "hissing" type of sound containing all frequencies within the audible range.

Synthesis systems often allow the user to select between several kinds of noise. The most common versions are white and pink. White noise is made up of the random distribution of all audible frequencies of equal amplitude between any equal bandwidths. White noise tends to sound like hiss or static. Pink noise is made up of the random distribution of all audible frequencies of equal amplitude between any octaves. Pink noise tends to sound more like gently blowing wind.

Example 17-1: Noise, random, audible frequencies made by synthesis, can be generated as such common kinds as "white" noise or "pink" noise.