LTAS and Laryngographic measures of adolescent singers performing in ‘Musical Theatre’ and ‘Classical’ styles

This paper examines results of a pilot study and a larger scale analysis of voice source and acoustic measures of young singers training in Musical Theatre styles. Over 100 subjects were taken from a variety of full time and part time stage schools in the UK, and also from the Brooklyn Youth Chorus Academy © (BYCA) in the USA. A Laryngograph was used to record and analyse vocal fold activity and derive vocal fold closed quotient (CQ) data, while a microphone was used to record the acoustic output for analysis using Long Term Average Spectra (LTAS).

A pilot study was undertaken at the BYCA, before extending the study to a larger sample across the UK. In accordance with other studies by the author and others, subjects were asked to read a short passage, sing a scale to the vowel /a/ and sing a verse of a well known song in different styles. The data was analysed for patterns using Laryngograph’s Speech Studio software and XLstat descriptive statistics.

Results of the pilot investigation of the data demonstrated that singers training in both Classical and Musical Theatre styles had lower vocal fold closed quotient (CQ) at most pitches when singing in a classical style than in a MT style. In many cases the difference was significant, and a one tailed student’s t-test showed a significant difference between the two groups over all pitches (Table 1). The spectral slope of the acoustic output was also found to be significantly shallower for MT singing than classical, particularly over the harmonics F0-F5. For the majority of notes analysed, the spectral slope was positive over F0-F3 with F1 and F2 considerably stronger than the fundamental, (table 2) suggesting resonance strategies particular to the musical theatre voice. ‘Classical’ voice had a consistently negative spectral slope, with harmonic amplitude weaker in almost all instances at all pitches than for the Musical Theatre style.

Results of the pilot study showed differentiation in both vocal function and acoustic output between the two different singing styles. The long term average spectra show a distinct increase in intensity of harmonics up to the 4th for the CCM voice compared to the classical style of singing. This indicates potential differences in both voice source and resonance strategies for the performer between the two different singing styles.