John Rahn, born on February 26, 1944, in New York City, is a music theorist, composer, bassoonist, and Professor of Music at the University of Washington School of Music, Seattle. A former student of Milton Babbitt and Benjamin Boretz, he was editor of Perspectives of New Music from 1983 to 1993 and since 2001 has been co-editor with Benjamin Boretz and Robert Morris.

Forte number and prime form

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There are three methods of computing Forte number and prime form. Allen Forte published the first in his 1973 book The Structure of Atonal Music, citing a 1961 article by Milton Babbitt.[1] The second was introduced in Rahn's Basic Atonal Theory and used in Joseph N. Straus's Introduction to Post-Tonal Theory, where it was declared that the two algorithms only differed in five cases: 5-20, 6-Z29, 6-31, 7-20, and 8-26.[2]

Forte (1973) and Rahn (1980) both list the prime forms of a set as the most left-packed possible version of the set. Forte packs from the left and Rahn packs from the right ("making the small numbers smaller" versus making "the larger numbers smaller").[3] Programmers tend to prefer Rahn's method, because the Rahn prime is easily computed by comparing sets in binary, whereas Forte's prime requires a more complex algorithm.[4]

References

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  1. ^ Forte 1973, p. 3.
  2. ^ Straus 1990, p. 28.
  3. ^ Nelson, Paul (2004). "Two Algorithms for Computing the Prime Form", ComposerTools.com.
  4. ^ Tsao, Ming (2007). Abstract Musical Intervals: Group Theory for Composition and Analysis, p.99, n.32. ISBN 9781430308355. Algorithms given in Morris, Robert (1991). Class Notes for Atonal Music Theory, p.103. Frog Peak Music.

Bibliography

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