Closed Quotient and Spectral Measures of Female Adolescent Singers in Different Singing Styles

Objectives. While quantifiable assessment of the singing voice is now commonplace, research on young (child and adolescent) voices is still in its infancy. There is still insufficient data on young people’s voices on which to model ‘norms’ in behaviour, particularly for Contemporary Commercial Music (CCM) such as Musical Theatre (MT). The objective of this study was to assess if quantifiable differences in vocal production and acoustic output of young singers exist between ‘classical’ and ‘musical theatre’ styles.
Study Design. The study was a prospective cohort study of 20 adolescent female singers aged 12-17 training their voices using a system which includes both 'classical' and ‘musical theatre’ styles.
Methods, The study examined Laryngographically derived Closed Quotient (CQ), Average Vowel Spectra (AVS) and Long Term Average Spectra (LTAS) measures of the sung voices of voices of singers in ‘classical’ and ‘musical theatre’ styles.
Results The spectral slope was shallower for the MT voice and Mean CQ was significantly higher across the pitch range when singing in a MT style than in a 'classical'. The second to fifth harmonics were stronger in the MT style than in classical, with a significant difference between the two styles.
Conclusion. The increase in intensity in the first five harmonics was disproportionately higher than the increase in CQ. Results therefore suggested that MT singing primarily uses change in resonance strategy rather than raised vocal tension to achieve the tonal changes associated with the genre.