Physiological and acoustic characteristics of the male music theatre voice.

Six male music theatre singers were recorded in three different voice qualities: legit and two types of belt ("chesty" and "twangy"), on two vowels ([e] and [ɔ]), at four increasing pitches in the upper limit of each singer's belt range (∼250-440 Hz). The audio signal, the electroglottographic (EGG) signal, and the vocal tract impedance were all measured simultaneously. Voice samples were analyzed and then evaluated perceptually by 16 expert listeners. The three qualities were produced with significant differences at the physiological, acoustical, and perceptual levels: Singers produced belt qualities with a higher EGG contact quotient (CQEGG) and greater contacting speed quotient (Qcs), greater sound pressure level (SPL), and energy above 1 kHz (alpha ratio), and with higher frequencies of the first two vocal tract resonances (fR1, fR2), especially in the upper pitch range when compared to legit. Singers produced the chesty belt quality with higher CQEGG, Qcs, and SPL values and lower alpha ratios over the whole belt range, and with higher fR1 at the higher pitch range when compared to twangy belt. Consistent tuning of fR1 to the second voice harmonic (2f0) was observed in all three qualities and for both vowels. Expert listeners tended to identify all qualities based on the same acoustical and physiological variations as those observed in the singers' intended qualities.

Vocal Qualities in Music Theater Voice: Perceptions of Expert Pedagogues.

OBJECTIVES/HYPOTHESIS: To gather qualitative descriptions of music theater vocal qualities including belt, legit, and mix from expert pedagogues to better define this voice type. STUDY DESIGN: This is a prospective, semistructured interview. METHODS: Twelve expert teachers from United States, United Kingdom, Asia, and Australia were interviewed by Skype and asked to identify characteristics of music theater vocal qualities including vocal production, physiology, esthetics, pitch range, and pedagogical techniques. Responses were compared with published studies on music theater voice. RESULTS: Belt and legit were generally described as distinct sounds with differing physiological and technical requirements. Teachers were concerned that belt should be taught "safely" to minimize vocal health risks. There was consensus between teachers and published research on the physiology of the glottis and vocal tract; however, teachers were not in agreement about breathing techniques. Neither were teachers in agreement about the meaning of "mix." Most participants described belt as heavily weighted, thick folds, thyroarytenoid-dominant, or chest register; however, there was no consensus on an appropriate term. Belt substyles were named and generally categorized by weightedness or tone color. Descriptions of male belt were less clear than for female belt. CONCLUSIONS: This survey provides an overview of expert pedagogical perspectives on the characteristics of belt, legit, and mix qualities in the music theater voice. Although teacher responses are generally in agreement with published research, there are still many controversial issues and gaps in knowledge and understanding of this vocal technique. Breathing techniques, vocal range, mix, male belt, and vocal registers require continuing investigation so that we can learn more about efficient and healthy vocal function in music theater singing.

Physiological and acoustic characteristics of the female Music Theater voice.

Three Music Theater 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 Theater singers performed each quality on two different vowels ([e], [ɔ]). Audio and electroglottographic (EGG) signals were recorded as well as the vocal tract impedance. In chesty belt and twangy belt, singers systematically tuned the frequency of their first vocal tract resonance (R1) to the second harmonic (2f(0)) up to C5. R1 remained lower in frequency for the legit quality. No tuning of the second vocal tract resonance (R2) was observed in any of these qualities although R2 frequency was significantly higher in both belt qualities than in legit. Closed quotient, degree of symmetry of the EGG waveform, sound pressure level (SPL) and the energy of the spectrum above 1 kHz were significantly greater in chesty belt than in legit but not significantly different between chesty belt and twangy belt qualities. A fourth quality ("mix") was explored in three singers. Different 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.