Traditionally, noise has been thought of as the outside of music and meaning. In systems theory, noise is disruption of the signal or message; in biological terms, it is associated with pain, in legal terms it is associated with disturbance. Noise is also that which has hitherto been excluded from being proper music, so can include radical new directions in musical form (Wagner, Coltrane) as well as noises deemed unmusical. The term noise implies a judgement about the type of sound, performance, or piece, not an inherent quality of it. This means that the idea of noise has always been historicized within music philosophy. Luigi Russolo proposed (in 1913) that noise was both an essential part of nature and a new reality of the industrialized metropolis. Purposeful use of noise, would, ironically, bring a new social harmony. John Cage expanded the definition of what could occur in the place of music, from silence (more accurately, the absence of silence) to machine sounds (turntables, radios, prepared pianos). In ...
