Objective:
The term “belt” has become a ubiquitous term in voice pedagogy, research, and in the commercial industry. It is often used to refer to a specific type of voicing commonly employed in contemporary music genres such as musical theatre, pop, and rock. Voice researchers have identified certain measurable parameters that may help distinguish belt from other styles. When compared to Western classical styles, for instance, belt singing may result in greater glottal adduction (Sundberg et al., 1993), an increased contact quotient (Estill, 1988), and an alignment of the first resonance with the second harmonic (Schutte and Miller, 1993). Voice pedagogues have identified certain strategies that may lead to these results, such as utilizing a higher laryngeal position, narrower pharyngeal space, and a wider mouth shape (LeBorgne and Rosenberg, 2025; Ragan, 2020; Davids and LaTour, 2020). Other investigators have found professional casting directors were better able to aurally identify the intended voicing styles (belt, mix, or legit) of professional singers compared to student singers (Maxfield and Manternach, 2017). Despite this work, however, the term belt lacks a codified, universally accepted definition. This project aims to compile and analyze scholarly sources that refer to and/or study belt voice in hopes of identifying the most frequent descriptors and commonalities.

Methods / Design:
We will undertake a comprehensive review of literature within major scientific databases, including PubMed, Scopus, Cochrane Library, ERIC, and Web of Science. We will determine inclusion and exclusion criteria and carry out meta analyses to identify common terms and descriptions, which will then be coded and synthesized using PRISMA reporting standards (Page, 2021). Risk of bias will be assessed using the Cochrane RoB-ME (Page, 2023) and certainty of evidence will be assessed using the GRADE approach (Brignardello-Peterson, 2024).

Results & Conclusions:
Examination of preliminary sources has already revealed a wide variety of terms, phrases, and characteristics that appear across the literature—both objective and subjective—to describe belt singing. Additional results are pending data collection and analysis. It is hoped that these findings will inspire future research and inform vocology practices, whether or not a consensus definition can yet be reached.