Sharpness: A perceptually based measure of the spectral dimension of musical timbre

Abstract

In order to assess the perceptual relationship between musical timbre and its physical properties, an effective measure should combine those factors considered important to perception with the common attributes of musical timbres. Sharpness is a perceptually based measure of timbre originally tested and put forth by Bismarck [Acustica 30, 146–172 (1974)] and later refined by Aures [Acustica 59, 130–141 (1985)] which applies a weighting to higher frequencies of a loudness pattern. Two-octave ranges from the brass, clarinet, saxophone, double reed, and string families of musical instrument timbres were analyzed across a musical dynamic range of pianissimo to fortissimo. Particular attention was paid to similarities in sharpness in three categories: Musical instrument families, instruments of like voice, and performance comparisons on the same instrument with different performers. Evidence suggests that most similarities in sharpness occur at the lower playing levels in every category. In addition, sharpness proved to be sensitive to idiosyncrasies of instrumental design and performer-specific techniques. Some comparisons to spectral centroids and centroids of loudness patterns [Grey and Gordon, J. Acoust. Soc. Am. 63, 1493–1500 (1978)] will be presented in addition to implications for application to subjective responses of musical blend.