Temporal and Spectral Cues for Musical Timbre Perception in Electric Hearing

Purpose: The purpose of this study was to investigate musical timbre perception in cochlear-implant (CI) listeners using a multidimensional scaling technique to derive a timbre space. Methods Sixteen stimuli that synthesized western musical instruments were used (McAdams, Winsberg, Donnadieu, De Soete, & Krimphoff, 1995). Eight CI listeners and 15 normal-hearing (NH) listeners participated. Each listener made judgments of dissimilarity between stimulus pairs. Acoustical analyses that characterized the temporal and spectral characteristics of each stimulus were performed to examine the psychophysical nature of each perceptual dimension.

Results: For NH listeners, the timbre space was best represented in three dimensions, one correlated with the temporal envelope (log-attack time) of the stimuli, one correlated with the spectral envelope (spectral centroid), and one correlated with the spectral fine structure (spectral irregularity) of the stimuli. The timbre space from CI listeners, however, was best represented by two dimensions, one correlated with temporal envelope features and the other weakly correlated with spectral envelope features of the stimuli.

Conclusions: Temporal envelope was a dominant cue for timbre perception in CI listeners. Compared to NH listeners, CI listeners showed reduced reliance on both spectral envelope and spectral fine structure cues for timbre perception.