The Acoustical Effect of Musicians' Movements During Musical Performances

Acoustic musical instruments act as dynamic sound sources communicating the expressive intentions of a performer to the audience in a dedicated spatial environment. From an acoustical point of view, the directivity of musical instruments is relevant both for the loudness and timbre of an instrument at a certain position in the loudness and timbre of an instrument at a certain position in the audience, as well as for the spatial characteristics of the generated sound field. Musical instruments, however, are dynamic sound sources always moved by musicians as an element of their performance on stage. This work aims at assessing the acoustical effect and the perceptual relevance of these movements. For this purpose, we have recorded solo musical performances with all standard orchestral instruments with an optical motion tracking system, as well as the corresponding audio signals. The effect of the movements was evaluated by analysing the spectral fluctuation and the time-dependence of room acoustical parameters in a virtual acoustic environment in anechoic and reverberant conditions. In a subsequent listening test, an auralization of the static and dynamic musical performance was presented to listeners by binaural synthesis, showing that the signal-related fluctuations are clearly audible both in anechoic and reverberant situations. We discuss different approaches how to consider these effects for the simulation of natural acoustic sources in virtual acoustic reality.