Technical noise is unpitched sound in which frequency and amplitude are related.
A computer is the only instrument that can generate technical noise.
Technical noise has colour. The colour of noise is loosely analogous to the colour of light. In the same way that there is white light in life there is white noise in music.
Technical noise includes all the frequencies in the sound spectrum. The different colours of noise all contain the same frequencies and these frequencies range over the entire spectrum. The difference between each colour of noise is due to the relationship between frequency and amplitude. This relationship is unique to each noise colour. That is what the phrase, technical noise, means. The sound of each noise colour demonstrates a different technical relationship between amplitude and frequency.
The following chapters look in turn at three of the most common colours of noise:
There is a veritable kaleidoscope of noise colours to explore in addition to white, pink and red noise. There is grey noise, blue noise, purple noise, and, most disturbing of all, black noise, which is silence.