p a p e r s

Vassilakis, P.N. (1999).  Chords as spectra, harmony as timbre.  J. Acoust. Soc. Am., 106(4/2): 2286 (presented at the 138th meeting of the Acoustical Society of America, Columbus, OH).


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’s Graduate Division.]