Singers' and Nonsingers' Perception of Vocal Vibrato

Vibrato, a small, nevertheless an important component in the singing voice is known to enrich the overall singing voice quality. However, in the perception of overall performance, it is often neglected. Singing performance is often appreciated by a mixed audience of those who love music, but not necessarily sing and other singers who may or may not be teachers of singing.

The objectives of the present study were aimed at investigating singers' and nonsingers' perception of vocal vibrato and its effect on the ratings of singer's overall performance.

Prerecorded audio samples of the chorus of a hymn (How Great Thou Art) as sung by 10 singers (both men and women) were played via a speaker to two groups of judges which consisted of three experienced singers and three experienced nonsingers. The singer judges (SJs) were vocal instructors in Western classical, music theater, pop, and contemporary styles. Seven parameters (presence of vibrato, rate, extent, conspicuousness, quality, periodicity, and type) related to vibrato were evaluated through auditory perception by these two groups of judges on a rating scale developed specifically for the study, and one parameter evaluated singer's overall performance.

Cohen's Kappa statistical analysis was used for inter-rater reliability within groups. Nonsinger judges (NSJs) within the group showed varied ratings as did SJs, yet SJs did have higher agreement than NSJs. Chi-square analysis was used across groups. Both groups were distinct from each other in their perception of vibrato. Ratings of singer's overall performance were not affected for NSJs, but certainly affected for SJ.

It could not be concluded that ratings on singer's overall performance was affected as a result of vibrato. Since vibrato is often over-ridden by the singer's voice. But a rare occasion can arise where a vibrato may not sound pleasant and can affect the listener's perception of the singer's performance. Often a feedback from listeners would help monitor singers' performance.