Isorhythm
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Isorhythm (iso or same) consists of an order of durations or rhythms, talea ("cutting", plural taleae), which is repeated within a tenor melody whose pitch content or series, color (repetition), varied in the number of members from the talea. The term was coined in 1904 by Friedrich Ludwig to describe this practice in 14th and 15th century polyphonic motets but is also used in motets of the middle ages, the music of India, and by modern composers such as Alban Berg, Olivier Messiaen, and John Cage. It may be used in all voices or only a few voices. In motets, it began in the tenor voice but was then extended to higher ones.
Ars nova composer Philippe de Vitry has been credited with the invention of the technique, but it "was neither an invention of Philippe de Vitry nor his exclusive property in the early fourteenth century." The isorhythmic construction was often varied through the use of strict or free rhythmic diminuation in the repetition of the color. (Hoppin 1978, p.363)
The talea was often a rhythmic mode. The color of isorhythm may be compared with the tone row of the twelve-tone technique's fixed order of pitches and varied durations. The modern musical innovation of integral serialism in the classes of Olivier Messiaen sprang from a study of the 12 tone compositions of Anton Webern and the isothythmic organization within motets of Guillaume de Machaut.
Coloration also refers to otherwise perfect notes colored red or with an open notehead to indicate the loss of 1/3 their duration, making them imperfect.
[edit] Source
- Hoppin, Richard H. (1978). Medieval Music. New York: W.W. Norton & Co. ISBN 0-393-09090-6.
