Inexperienced Listeners' Perception of Timbre Dissimilarity Within and Between Voice Categories

Using stimuli produced by classically trained female singers, this study sought to examine how inexperienced listeners' ratings of timbre dissimilarity relate to singer categorization, both between and within voice category.

Stimuli were produced by six mezzo-sopranos and six sopranos classically trained female voice students at three pitches, C4, G4, and F5. Within each category, mezzo-soprano and soprano, three singers were classified as lighter in timbre and three were classified as heavier in timbre. At each pitch, the 12 sung stimuli were combined in all possible pairs and presented to 56 inexperienced listeners who judged each pair for the degree of timbre dissimilarity using a visual analog scale. All stimuli also were rated by expert voice professionals in two dimensions: (1) voice category and (2) vocal weight.

Multidimensional scaling (MDS) dimensions agreed with teacher-determined voice category at C4 and teacher-determined vocal weight at G4 and F5. MDS dimensions also correlated with single-note ratings of voice category and vocal weight provided by expert listeners who were unfamiliar with the singing voices used in this study. With limited exceptions, no single acoustic variable predicted the MDS dimensions that resulted from the inexperienced listeners ratings of timbre dissimilarity; however, weighted linear combinations of acoustic variables were highly predictive of numerous MDS dimensions.

In spite of a lack of both range and tessitura information, timbre dissimilarity ratings provided by inexperienced listeners yielded MDS dimensions that accurately predicted voice categories and vocal weight and that highly correlated to expert listeners ratings of these two parameters.