Perception of Non-Vibrato Sung Tones: A Pilot Study

Abstract

Singers are often asked to sing with a non-vibrato production. The term non-vibrato is problematic in that it is not possible for a human to sing a tone without fundamental frequency variation. Whether a singer achieves a quality of tone that is perceived as non-vibrato is an aurally subjective matter. The specific aim of this study was to determine when a tone is perceived as non-vibrato by a population of singers, voice teachers, choir directors, and speech pathologists. Using voice samples that exhibit a variety of vibrato rates and extents, the investigators sought to determine (1) if there is a threshold for the perception of non-vibrato tone with regard to vibrato extent; (2) if vibrato rate, given similar vibrato extent, does affect the perceptual threshold of non-vibrato tone; and (3) if there are differences in the perceptual threshold of non-vibrato tone across the different professions of the research subjects. Survey. Participants responded to an online survey featuring 40 randomized samples of soprano voices singing [ɑ] with a variety of vibrato rates and extents. Some samples were repeated to test subject response reliability. Results indicate that a perceptual threshold exists with regard to vibrato extent. However, vibrato rate significantly affected where this extent threshold occurred for the participants. Vibrato extent and rate work together to affect perception of non-vibrato tone. Significant differences were not found across the different groups.