ISIS, AN ALTERNATIVE APPROACH TO SOUND WAVES
Clarence Barlow · University of Michigan Library Repository · 2005
ISIS, for 'Intra-Samplar Interpolating Sinusoids', is a means of mathematically interpolating sine wave segments between the samples of a sound wave recording (the word "sample" is here used as in "sample rate").The sound wave is thus representable as a sequence of sine-tone pitches in extremely small time windows in the microsecond domain, rendering the wave audible as a rapid sine-tone 'melody' e.g. by slowing it down 4000 times, a feature given neither by regular time-stretching methods nor by cubic splineinterpolations. Conversely, this ISIS-extracted sequence can be accelerated to regain the original sound; indeed any melody can be similarly sped up to form a sound wave.The main application of ISIS is at present in the technical unification -for compositional purposes -of the micro-and the macro-temporal domains (pitch, timbre and rhythm) into one comprehensive field.Methodologically, ISIS comprises the three areas Analysis, Morphosis and Synthesis, described below after the following historical account ('Morphosis' is a biological term for the "sequence of development or change in an organism or in any of its parts").