Vocal warm-up produces acoustic change in singers' vibrato rate.

Vibrato rate and vibrato extent were acoustically assessed in 12 classically trained female singers before and after 25 minutes of vocal warm-up exercises. Vocal warm-up produced three notable changes in vibrato rate: (1) more regularity in the cyclic undulations comprising the vibrato rate of a note, (2) more stability in mean vibrato rates from one sustained note to the next, and (3) a moderating of excessively fast and excessively slow mean vibrato rates. No significant change was found for vibrato extent. The findings indicate that vocal warm-up may regulate vibrato rate. Thus tone quality, which is strongly linked to vibrato characteristics, may undergo positive change as a result of vocal warm-up.