Identification of the separate tones heard in a woodwind multiphonic sound as grouped subsets of its spectral components

Abstract

The spectrum of a woodwind multiphonic sound consists of a large number of unharmonically related heterodyne components. Musicians have a need to notate these sounds. They usually write “chords” whose individual notes each represent a perceived subset of spectral components. Each subset normally includes components that are in quasiharmonic relationship, and its perceived pitch approximates that of a corresponding tone having exact harmonics. The variety of subsets which are perceived at the same pitch is illustrated by the following examples, all of which match the ordinary note C4 a whose components are multiples of 261.6 Hz: (278,467, 620, 786, 1046); (267, 534, 641,764, 1071); (275, 512, 620, 796, 1026); (272,544, 622, 819, 1033). Pitch assignment is not particularly sensitive to component amplitude, making tonal perceptions stable despite the vagaries of sound transmission in a room. Various clarinet and oboe multiphonics are discussed and illustrated.