Speaker
Description
Overhead reflector (canopy) systems are critical in shaping the acoustic environment for symphony orchestras. While previous research has focused on the timing, strength and frequency content of first-order reflections and ensemble conditions, the influence of canopies on the late reverberant field remains under-explored. This study investigates how large-scale monolithic canopies affect the spatial development of the sound field, hypothesising that high stage-coverage ratios lead to a partial acoustic decoupling of the volume above the canopy from the primary hall volume. Empirical observations made during the commissioning of variable-acoustics concert halls suggest that canopy height alters the late reverberant sound, not only the early reflected sound. To quantify these effects, spatial room impulse responses (SRIRs) were captured in a concert hall across multiple canopy height configurations using a spherical microphone array. The RIRs were encoded into Higher-Order Ambisonics (HOA) to provide high-resolution spatial analysis and facilitate accurate auralisation. This work presents an investigation of the spatial energy distribution and late-part decay characteristics associated with changes to canopy height. The findings will be used to guide future studies in this area, including perceptual studies aimed at understanding how musicians and audiences perceive the orchestral sound in relation to overhead reflectors.