Interpersonal synchronization in ensemble singing: the roles of visual contact and leadership, and evolution across rehearsals

Interpersonal synchronization between musicians in Western ensembles is a fundamental performance parameter, contributing to the expressiveness of ensemble performances. Synchronization might be affected by the visual contact between musicians, leadership, and rehearsals, although the nature of these relationships has not been fully investigated. This thesis centres on the synchronization between singers in a cappella singing ensembles, in relation to the roles of visual cues and leadership instruction in 12 duos, and the evolution of synchronization and leader-follower relationships emerging spontaneously across five rehearsals in a newly formed quintet. In addition, the developmental aspects of synchronization are investigated in parallel to tuning and verbal interactions, to contextualise synchronization within the wider scope of expressive performance behaviours.
Three empirical investigations were conducted to study synchronization in singing ensembles, through a novel algorithm developed for this research, based on the application of electrolaryngography and acoustic analysis. Findings indicate that synchronisation is a complex issue in terms of performance and perception. Synchronization was better with visual contact between singers than without in singing duos, and improved across rehearsals in the quintet depending on the piece performed. Leadership instruction did not affect precision or consistency of synchronization in singing duos; however, when the upper voice was instructed to lead, the designated leader preceded the co-performer. Leadership changed across rehearsals, becoming equally distributed in the last rehearsal. Differences in the precision of synchronization related to altered visual contact were reflected in the perception of synchronization irrespective of the listeners’ music expertise, but the smaller asynchrony patterns measured across rehearsals were not. Synchronization in the quintet was not the result of rehearsal strategies targeted for the purpose of synchronization during rehearsal, but was paired with a tendency to tune horizontally towards equal temperament (ET), and to ET and just intonation in the vertical tuning of third intervals.