Stage Acoustics in Eight Australian Concert Halls: Acoustic Conditions in Relation to Subjective Assessments by a Touring Chamber Orchestra

Chamber musicians' acoustic impressions of auditorium stages: Relation to spatial distribution of early reflections and other parameters

“…Barron 2 studied musicians' impressions in a hall with an adaptable stage enclosure and found a possible preference for a close ceiling reflection. Others [3][4][5][6][7] have proposed acoustic parameters designed to be measured on stage. These stage acoustical parameters are usually either energy ratios of parts of an impulse response, or of a pair of impulse responses, and may be stated in the general form…”

“…This number of factors is far higher than in previous work, where not more than two factors were found from questionnaires with orchestral musicians. 3,4 Besides the use of the more established omnidirectional parameters listed in ISO 3382-1, recent studies have also examined the directionality of on-stage sound fields, 6,7,[18][19][20] including the use of microphone arrays to capture highresolution spatial information. In a series of studies, Ueno et al 18,21,22 developed a method for measuring on-stage auditorium impulse responses using a six-cardioid microphone system (with microphones mutually orientated at 90 ) primarily for real-time, spatially realistic, and measurementbased auralizations of the stage environments in the laboratory.…”

“…Guthrie explored findings about LQ 7-40 Top/Sides by examining variations on a simple stage enclosure, concluding that high ceilings and stage walls close enough to give early reflections within 30 ms of the direct sound consistently provided "optimum" conditions, based on earlier auralization work. 6 In preliminary work exploring spatial characteristics of sound fields on stage using higher-order microphone arrays, Panton et al 7 reported a relationship between chamber musicians' assessments, and a spatially defined parameter TS 20-50 , which is the ratio of energy from "top" to that from the sides on stage arriving over 20-50 ms. However, this work had several acknowledged limitations, and had identified future areas of improvement.…”

“…This included considering back wall reflections, i.e., incorporating the "back" region into a spatial ratio, similar to the top-side spatial ratio (TS 20-50 ), 7 and considering the usefulness of architectural measures, such as stage dimensions in Dammerud. 4 Statistical analysis in the paper by Panton et al 7 was also limited to regression using median values of the musicians' rating of the OAI per hall. Such an analysis ignores the repeated-measures design of the study, wherein the same musicians are rating several halls.…”

“…(a) to determine the relationship between existing omnidirectional stage acoustic parameters, and chamber musicians' subjective preferences: In the current paper, as in earlier studies, 3,4,12 the relevance of early reflections on stage (as characterized by EDT on stage, ST Early , G Early ) to musicians is investigated, as well as the relevance of late reflections on stage (as characterized by T 30 , ST Late , and G Late ); (b) to examine ways in which spatial analysis can be used to characterize onstage sound fields and subsequently determine the relationship between these spatiallydefined acoustic parameters, and the subjective preferences of chamber musicians: As noted above, several recent studies have proposed that the spatial distribution of reflection on stage is important. 4,6,7,19 In the current study, the ratio of reflections from above to (i) those from the sides, and (ii) those from the horizontal directions, i.e., sides and back of stage, are considered. Furthermore, the importance of simple architectural ratios of the stage is explored.…”