Perceptual, acoustic and physiological characteristics of music theatre singing

Abstract

Most of the scientific research on the singing voice has focused on classical and operatic singing. Music theatre and contemporary voice are growing in popularity within Western musical culture, but little is known about safe and effective training methods, aesthetics and vocal health for students of these vocal styles. This research aims to combine pedagogical experience and objective data gathered from experimental studies in order to develop a more complete understanding of the perceptual, physiological and acoustic features of music theatre vocal styles. In study one, a series of semi-structured interviews were conducted with experienced vocal pedagogues from Australia, USA, UK and Asia to gather perceptual data on music theatre vocal qualities. Teachers identified the differences between classical and music theatre vocal production, including belt, legit and mix, and discussed vocal function, physiology, pitch range, style and pedagogical approaches to the training of music theatre singers. Interview data was coded and analysed and critically evaluated in the context of recent published research about music theatre and contemporary commercial music (CCM) vocal qualities. In the second study, three music theatre vocal qualities (“chesty belt”, “twangy belt” and “legit”) were investigated in female singers at their overlap range between F#4 – D5 (~370-600 Hz). Six experienced music theatre singers performed each quality on two different vowels ([e], [ɔ]). Audio and electroglottographic (EGG) signals were recorded as well as the vocal tract impedance. Chesty belt was significantly different from legit in all parameters, while chesty and twangy belt qualities only differed in frequencies of the second vocal tract resonance (fR2). A fourth quality (“mix”) was explored in three singers. Differing production strategies were observed for each singer, with values of spectral, glottal and vocal tract descriptors found in between those measured for legit and chesty belt qualities. In the third study, three contrasting qualities (chesty belt, twangy belt, legit) were investigated in six male music theatre singers. Two vowels ([e], [ɔ]) were produced on four increasing frequencies at the upper limit of the singer’s belt range (~250-440 Hz). Audio and electroglottographic (EGG) signals were recorded simultaneously with the vocal tract impedance. Singers produced belt qualities with significantly different production characteristics at the glottis, vocal tract and acoustic spectrum from legit, especially in the upper pitch range. Significant differences between chesty and twangy belt were also observed in the higher pitch range. A consistent tendency to tune the first vocal tract resonance (fR1) to the second voice harmonic (2f0) was observed in all three qualities, supporting the idea that belt and legit may differ by slight variations in voice quality rather than as fundamentally distinct modes of production in the male voice. The implications of this research are significant to the development of appropriate pedagogical strategies for the music theatre voice. These findings suggest that the training of music theatre singers should include both contemporary and classical approaches to vocal technique, especially for female singers.