Auditory sensation of impulsivity and tonality in vocal fry

Abstract

Vocal fry is a phonation type characterized by nearly complete vocal tract damping during the closed glottal cycle phase, caused by a low vocal frequency in combination with a long glottal closed phase. Auditorily, vocal fry is characterized by the sensation of individual glottal cycles. Vocal fry may be (para-)linguistically relevant, but it may also be a symptom of a voice disorder. The aim of the study is to develop predictive models of the presence of vocal fry based on data from auditory experimentation using synthetic stimuli. Predictors are the vocal frequency, the glottal open quotient, and the glottal pulse skewness. The vocal tract is kept constant. Tests are conducted with stimuli that are temporally homogeneous in terms of voice quality, as well as with stimuli that contain neutral-fry-neutral voice quality transitions. Listeners rate tonality, impulsivity, and naturalness of stimuli on 7-point scales, as well as the presence of vocal fry on a dichotomous scale. Results show that perceived vocal fry is correlated with an increase in perceived impulsivity and a decrease in perceived tonality of the voice. The most important predictor of vocal fry is vocal frequency, whereas open quotient and skewness appear to play a minor role.