Developing a Single Comparison Stimulus for Matching Breathy Voice Quality

Abstract

Purpose In this experiment, a single comparison stimulus was developed as a reference in a perceptual matching task for the quantification of breathy voice quality. Perceptual judgments of a set of synthetic voice samples were compared to previous data obtained using multiple comparison stimuli “customized” for different voices (Patel, Shrivastav, & Eddins, 2010). Method Five male and 5 female samples of the vowel /a/ were selected from the Kay Elemetrics Disordered Voice Database and resynthesized using a Klatt synthesizer. Eleven samples were created for each base voice by manipulating the aspiration noise level. Five samples from each continuum were evaluated in a perceptual matching task in which a single sawtooth and noise comparison stimulus was used to obtain breathiness judgments. Linear regression was used to compare measurements obtained using the new comparison stimulus against the customized comparison stimuli. Results Results indicated that the noncustomized sawtooth comparison provides reliability and perceptual distances between stimuli similar to those obtained using customized comparison stimuli. Conclusion A single-variable matching task using a single comparison stimulus can be used to obtain perceptual estimates of breathiness across voices and experiments in a laboratory setting. This technique will help develop models of voice-quality perception.