John Rahn

John Rahn is a music theorist, composer, and Professor of Music in 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 until 1993 and since 2001 has been co-editor with Benjamin Boretz and Robert Morris.

Forte number and prime form

There are two methods of computing Forte number and prime form, the second introduced in John Rahn's Basic Atonal Theory and used in Joseph N. Straus's Introduction to Post-Tonal Theory. This affects sets 5-20, 6-Z29, 6-31, 7-20, and 8-26.

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"[1]). However, these only differ in five instances[1] and are the result of different algorithms (Rahn's being preferred by programmers).[2]

Bibliography

References

  1. 1.0 1.1 Nelson, Paul (2004). "Two Algorithms for Computing the Prime Form", ComposerTools.com.
  2. 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.

External links