Fusion and consonance relations for tones with inharmonic partials

Tones with inharmonic partials were generated on the Sampson Digital Synthesizer according to the algorithm. Fn = F1alog 2n, where Fn is the frequency of the nth partial and a determines the degree of stretching/shrinking of the octave. Subjects noted a bell or gonglike quality for stretched and shrunk tones. Subjects were asked to make judgments on the degree of fusion (unitary sensation of pitch). For individual tones a “pulling apart” of tones as a function of increasing a was discovered. Dyads, triads, melodic, and harmonic passages were also presented. Melodic relationships seem to hold throughout the range of 60% shrunk to 200% stretched (a = 1.2 → a = 4), whereas certain harmonic relationships break down. Preliminary results indicate that this harmonic breakdown is due to context and is not an individual property of the chord.