Tudor’s realization of Variations II, composed by John Cage as a birthday present for Tudor in 1961, is illustrated here as one of the earliest examples of a piece Tudor conceived for live electronic performance. Cage’s original notation consisted of five points and six lines on eleven individual plastic sheets and instructed the performer to create measurements between the dots, representing sound events, and the lines, representing parameters of sounds (amplitude, duration, overtone structure, frequency (pitch), point of occurrence, number of sounds structuring each event). The resultant measurements defined the parameters of each sound event.
http://www.getty.edu/research/tools/guides_bibliographies/david_tudor/av/variations.html
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