Singing voice: acoustic parameters after vocal warm-up and cool-down.

Purpose: The aim of this study was to evaluate the effect of the vocal warm-up and cool-down on the singing voice through Fundamental Frequency (F0), Jitter, Shimmer and harmonics-to-noise ratio (HNR). Methods: Thirty-two female singing students were recorded four times while uttering the vowel [a] for at least 5''. The first two recordings were collected before and after a vocal warm-up session and the last two before and after a vocal cool-down session. Between those sessions the participants underwent an intense vocal activity. Results: Results showed significant variations in the average values of the parameters measured. The mean value of the F0 after intense vocal activity turned to be higher than the one measured before the warm-up session, as well as the mean F0 measured after singing compared to the one measured after the vocal warm-up. On the other end, the mean F0 after the vocal cool-down resulted to be lower than that measured before. After the vocal warm-up session Jitter and Shimmer decreased while HNR increased. In addition, a decrease was detected in comparison with the average value of Jitter and Shimmer before vocal warm-up and after vocal cool-down, whereas HNR increased. There was also a decrease between the Shimmer before the vocal warm-up and after an intense phonatory activity while HNR increased. Conclusions: Our study highlights the effect of the vocal warm-up on acoustic parameters. The reduction in F0 observed after the cool-down session confirms its positive effect in helping professional vocal recovery and reducing vocal fold tension.