Quantifying Vocal Repertoire Tessituras Through Real-Time Measures.

Abstract

Voice teachers use anecdotal evidence and experience in determining the appropriateness of repertoire for each student's development. Tessitura is important in that determination, but until recently a straightforward, repeatable, and quantifiable method for determining tessitura has not existed. However, technology exists to provide the means to estimate the tessituras of standard vocal repertoire by measuring sung pitch (fundamental frequency) and vocal dose (amount of phonation) in real-time performance. The purpose of this study was to examine the combined use of tessituragrams, Voice Range Profiles (VRPs), a singer's self-perception of a performance, and expert listeners perception of a performance towards the goal of a more systematic way of selecting appropriate voice repertoire for singers. The following research questions guided this investigation: 1) How do Performance Range Profiles (PRPs, performance-based tessituragrams computed from neck skin surface vibration during singing), compare to score-based tessituragrams of the same selection in the same key? 2) How do PRPs of the same vocal score compare when performed in three different keys? 3) How do singer VRPs compare with PRPs of three performances of a score, each sung in a different key? and 4) How do singer and expert panel perceptions of the selection's "fit" in three different keys compare with the alignment of each singer's VRP to their PRPs? Four female singers and five expert voice pedagogues were enlisted to address these questions. The distribution (histogram) of the score-based tessituragram closely matched the distribution of performance-based tessituragrams (PRP), suggesting that score-based tessituragrams have promise in accurately reflecting the performance-based tessitura of a musical vocal work. Acquired data revealed relationships of practical importance between score-derived tessituragrams, PRPs, acquired VRPs, and singer perceptions of ease in singing. These data suggest that score-based tessituragrams aligned with singer VRPs show promise in repertoire selection. However, there was only a minor relationship between expert panel perceptions of ease in singing and the acquired PRPs or singer perceptions of ease. Creation of a score-based tessituragram database could be combined with singer VRPs to assist in appropriate repertoire selection.