Chords as spectra; harmony as timbre
Pantelis N. Vassilakis · The Journal of the Acoustical Society of America · 1999
Traditionally, musical chords have been understood as combinations of discrete tones or as the layering of intervals. From the listener’s point of view, however, chords often fuse into a single perceptual unit with a specific, readily recognized character (i.e., major/minor.) When chordal fusion occurs, a chord’s distinct character can be understood as its timbre in terms of a single inharmonic spectral distribution, rather than a combination of discrete harmonic spectra. The present study examines the relationship between spectral distribution described in terms of (i) spectral centroid (center of amplitude-weighted frequency distribution); (ii) spectral bandwidth (spread of frequency distribution); (iii) spectral density (average number of components per critical band); and (iv) spectral inharmonicity (defined in terms of sensory consonance/dissonance curves) — and perceptual identity of complex tone combinations. It addresses the perceptual equivalence of chord inversions (root, first, second inversion of a single chord category) and the perceptual difference between different chord categories (major/minor) in terms of spectral inharmonicity rather than interval layering. Preliminary results suggest that this study can be extended to examine harmonic motion as a motion between spectral distributions with various degrees of sensory consonance/dissonance, rather than melodic motion between leading tones. [Work supported by UCLA, Graduate Division.]