Scientific data in literature show that the singers of classical lyric orchestras are exposed to high risk of damage to the vocal apparatus due to the intense effort they have to face during the artistic performances. Vocal effort in a group of singers of a classical orchestra of a National lyric theatre is considered here. A specific protocol of measures has been defined with the aim of evaluating the quality of vocal emissions before and after the artistic performance during the rehearsal of a grand opera. Voice quality was parametrised in terms of average pitch value, quality ratio, vibrato frequency and extension. A statistically significant difference was found between the quality ratio and the standard deviation of the fundamental frequency F0 and of the vibrato extension in the exercises executed before and after the vocal performance. These results confirm the hypothesis that such parameters are related to the laryngeal effort.

Index Terms. lyric singers, vocal effort, vocal quality