Objective Assessment of Acoustic Conditions for Symphony Orchestras

At present the most common measures for assessing stage acoustic conditions on concert hall stages are the Support measures – ST_earlyand ST_late. These measures are based on monophonic omnidirectional responses obtained at 1 m from the sound source, on a stage without a full symphony orchestra (or similar group of people) present. Both objective and subjective studies have been conducted, the latter using questionnaires with several orchestras and dialogue with musicians. Objective studies involved measurements on real stages of the Support measures and other acoustic measures such as T, EDT, C₈₀, G_7–50, G_e( G_0–80) and G_l( G_80–∞) as well as a set of proposed architectural measures. These have been complemented with analytical as well as scale and computer model investigations into sound behaviour on both empty and occupied concert stages. The major results from these studies are presented in this paper along with a discussion of alternative approaches for assessing stage acoustic conditions. One important result concerned the relevance of directions from which early reflections arrive regarding perceived ensemble conditions, an objective factor not assessed by the Support measures.