Noise and Tremor in the Perception of Vocal Aging in Males

Objective/Hypothesis To specify a set of acoustic cues for vocal aging and to establish their perceptual relevance. Study Design Perceptual testing. Methods To identify the acoustic and perceptual correlates of the aging voice, voice quality [in conjunction with speaking rate and fundamental frequency (F0)] was systematically manipulated using resynthesis to determine its effect on perceived age. Ten young male voices were resynthesized using two levels of noise (random modulation of F0 contour) and two levels of tremor (constant modulation of F0 contour with a low-amplitude wave) under a speaking-rate manipulation (an increase in speaking rate that is common to older male voices). These materials were submitted to 40 naive listeners in an age-estimation task. Two sets of comparison materials were also included for evaluation: unmanipulated samples from a 150 voice database of young, middle-aged, and older voices and disordered voice samples representing natural manifestations of the voice qualities of interest. Results Speaking rate, highest degree of tremor, and highest degree of noise all shifted, in an additive manner, the mean perceived age of the young male voices by a maximum of 12 years on average; individual voices were observed being shifted by a generation. Fundamental frequency manipulations had no significant effect on perceived age. Conclusions Voice quality (both tremor and noise) and speaking rate are all perceptually relevant cues of age in male voices.