The role of auditory feedback in sustaining vocal vibrato

Abstract

Vocal vibrato and tremor are characterized by oscillations in voice fundamental frequency (F 0 ). These oscillations may be sustained by a control loop within the auditory system. One component of the control loop is the pitch-shift reflex (PSR). The PSR is a closed loop negative feedback reflex that is triggered in response to discrepancies between intended and perceived pitch with a latency of 1 00 ms. Consecutive compensatory reflexive responses lead to oscillations in pitch every ~200 ms, resulting in ~5-Hz modulation of F 0 . Pitch-shift reflexes were elicited experimentally in six subjects while they sustained /u/ vowels at a comfortable pitch and loudness. Auditory feedback was sinusoidally modulated at discrete integer frequencies (1 to 10 Hz) with ±25 cents amplitude. Modulated auditory feedback induced oscillations in voice F 0 output of all subjects at rates consistent with vocal vibrato and tremor. Transfer functions revealed peak gains at 4 to 7 Hz in all subjects, with an average peak gain at 5 Hz. These gains occurred in the modulation frequency region where the voice output and auditory feedback signals were in phase. A control loop in the auditory system may sustain vocal vibrato and tremorlike oscillations in voice F 0.

Central nervous system control of the laryngeal muscles in humans

“…Speakers are not always aware, however, that they are making these corrections. Recently, these compensatory responses were shown to play a role in ongoing speech and singing control (Leydon et al, 2003;Xu et al, 2004). Interestingly, pitch shift responses were greater in persons who speak tonal languages than in English speakers.…”

Audio–vocal responses of vocal fundamental frequency and formant during sustained vowel vocalizations in different noises

“…A faster pulsation of F0, usually between 3 Hz and 8 Hz, is known as vocal vibrato. A vibrato has been considered associated with active modulation of the laryngeal motor neuron pool (Hsiao et al, 1994) and the control of auditory system (Leydon et al, 2003). It can be deliberately produced, suppressed, or modified after training.…”

Estimating Subglottal Pressure via Airflow Interruption with Auditory Masking

“…The pitch-shift reflex is a closed loop negative feedback reflex that occurs in response to a difference between intended and perceived pitch. It has an approximate latency of 100 ms (16). Changes in phonation due to changes in the intensity of auditory feedback have also been studied.…”