On Measurements of Stage Acoustic Parameters: Time Interval Limits and various Source–Receiver Distances

Abstract

The most widely recognized objective stage acoustic parameters are the Early Support (ST early ) and Late Support (ST late ). In these parameters the early and late reflected sound energy is measured within a certain time interval. Different time interval limits have been proposed for the stage acoustic parameters but there is no agreement on the preferable limits. There is a growing interest to measure stage acoustic parameters at various source to receiver distances. In this paper the influence of perceptual and architectural parameters, synchronicity, source to receiver relationship and the measurement system on stage acoustic parameters is discussed. Based on existing and new insights an optimization and extension of the ST parameters is proposed such that they can be measured at any distance between source and receiver using the most appropriate time interval limits. Theoretical assumptions were checked and confirmed based on systematic analyses of measured results for different concert hall stages with various conditions and various source to receiver distances. SummaryThe most widely recognized objective stage acoustic parameters are the Early Support (ST early )and Late Support (ST late ). In these parameters the early and late reflected sound energy is measured within acertain time interval. Different time interval limits have been proposed for the stage acoustic parameters butthere is no agreement on the preferable limits. There is agrowing interest to measure stage acoustic parameters at various source to receiver distances. In this paper the influence of perceptual and architectural parameters, synchronicity,source to receiver relationship and the measurement system on stage acoustic parameters is discussed. Based on existing and new insights an optimization and extension of the ST parameters is proposed such that theycan be measured at any distance between source and receiveru sing the most appropriate time interval limits. Theoretical assumptions were checked and confirmed based on systematic analyses of measured results for different concert hall stages with various conditions and various source to receiverdistances. PACS no. 43.20.El, 43.55.Br,43.58.Gn 776 ©S.Hirzel Verlag · EAA Wenmaekers et al.:M easurements of stage acoustic parameters ACTA ACUSTICA UNITED WITH ACUSTICA Vol. 98 (2012)

How orchestra members influence stage acoustic parameters on five different concert hall stages and orchestra pits

“…This modification leads to differences (averaged over 10 concert hall stages) between ST early,d and ST early ranging from only 0.3 dB at position S4 close to the stage edge up to 2.7 dB for position S1 often close to 2 m from the back wall. 2 Results for the original ST early are also discussed in the current study. The difference between ST late,d and ST late is negligible: only 0.02 dB from an average of 11 concert hall stages.…”

“…For comparing early reflected sound levels on different stages, the exact choice of time limit is not that relevant. In an earlier paper, 2 it was shown that different time windows on either early or late reflected sound would not lead to a difference in ranking of eight different halls. Therefore, the extended and modified versions of the well-established ST parameters were a logical step and are considered being most appropriate for current research.…”

“…2 In ST early,d at 1 m the lower limit has changed from 20-100 ms to 10-100 ms. It was concluded 2 that this is necessary to include very early reflected sound and that this is possible without including the direct sound or floor reflection.…”

“…Much research in the field of stage acoustics has focused on defining physical parameters to predict musicians' perception of the acoustics. The early and late support parameters ST early and ST late were introduced by Gade 1 and modified to ST early,d and ST late,d by Wenmaekers et al 2 These ST parameters measure the amount of sound energy arriving early and the sound energy arriving late on stage. Other suggestions for parameters are the early decay time (EDT), early ensemble level 1 (EEL), and the early sound strength, 3 or G early .…”

“…Extensive information on the various (other) parameters that have been used in stage acoustics can be found elsewhere. 2 However, there is still a lack of agreement on what stage designs are preferred by musicians and what physical parameters are of importance. 5 Studies using questionnaires with orchestra members judging concert halls did not consistently reveal a correlation between perceptual attributes and physical parameters.…”