What is the Physiological Difference Between Belt and Mixed Belt?
– By Elle Holiday
The difference between mixed belt and belt (or ‘legit belt’) can be measured by comparing the physiological and laryngeal characteristics of open and closed quotients (CQ).
OPEN & CLOSED QUOTIENT
Open quotient (OQ) and CQ are terms used to describe the proportion of time the vocal folds spend in the open and closed phases during a vibratory cycle. These quotients can affect the quality and intensity of the voice. (Bourne & Garnier, 2012; Sundberg, 2014).
A higher CQ leads to a more powerful and intense sound, which is characteristic of belting. On the other hand, mixed belt techniques have a more balanced or slightly lower CQ compared to belt, as they involve a combination of chest and head voice qualities and reduced vocal fold tension. (Bourne & Garnier, 2012; Sundberg, 2014).
BELT
Belt technique involves a longer closed quotient and higher subglottic pressures. The closed quotient refers to the proportion of time the vocal folds are closed during a full cycle of vocal fold vibration, while subglottic pressure is the air pressure required to initiate vocal fold vibration.
MIXED BELT
Mixed belt is characterised by moderate subglottal pressure and moderate glottal adduction (closure of the vocal folds) (Sundberg et al., 1993). This technique is thought to be less muscularly demanding than belting, resulting in a more balanced open and closed quotient.

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Whether you are new to singing, a seasoned singing teacher or singer, our VocaLab Belt Building Masterclass will help you take your belt to the next level. In this masterclass, we explore:
– Anatomy, physiology and classification of belt
– Exercises to strengthen your belt
– Exercises to extend your belt range
– How to problem-solve your belt
– Practical strategies for incorporating belt into songs
– Creating your very own ‘Belt Training Program’
SUMMARY
While mixed belt and belt techniques have different open and closed quotients, it is crucial to recognise that individual singers may have varying vocal characteristics depending on their training, technique, and physiological factors.
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REFERENCES
• Bourne, T., & Garnier, M. (2012). Physiological and acoustic characteristics of the female music theatre voice in “belt” and “legit” qualities. Journal of Voice, 26(5), 664.e19-664.e26.
• Lawrence, V. (1979). An Investigation of the Laryngeal Characteristics of Belt and Legitimate Voice Production. Journal of Research in Singing, 2(2), 3-21.
• Sundberg, J., Gramming, P., & Lovetri, J. (1993). Comparisons of Pharynx, Source, Formant, and Pressure Characteristics in Operatic and Musical Theatre Singing. Journal of Voice, 7(4), 301-312.
• Sundberg, J. (2014). Science of the Singing Voice. Northern Illinois University Press.
