Comparisons of auditorium acoustics measurements as a function of location in halls

John S. Bradley, A. C. Gade, Gary W. Siebein
1993 Journal of the Acoustical Society of America  
By 1980 the understanding of acoustics for concert halls had reached an interesting stage. Two German studies at G•ttingen and Berlin with dummy head recordings had gone a long way to determining the important subjective and objective dimensions. However the influence of architectural form on subjective acoustic conditions was much less well established. There were two possible routes: testing acoustic scale models or full-size auditoria. With access to sufficient full-size auditoria, the
more » ... was the obvious choice since it also allowed true subjective assessment. The acoustic survey of British auditoria involved both objective measurements and subjective assessments in over 40 auditoria including concert halls, drama theaters, opera houses, and multipurpose spaces. The whole exercise has now been published [M. Barron, Auditorium •4coustics and •4rchitectural Design (Chapman & Hall, London, 1993)]. In concert halls a major conclusion of the subjective exercise was that halls with good reputations score well with regard to several attributes, such as reverberance, envelopment, and intimacy. Several novel observations on the effect of design details will also be discussed. 9:30 laAA2. Effects of measurement procedure and equipment on average room acoustic measurements. A.C. Gade (Acoust. Lab., This paper reports the results of a measurement tour of nine U.S. concert halls. Three measurements teams, from the University of Florida, the National Research Council of Canada, and the Technical University of Denmark, made parallel sets of measurements using their own equipment and procedures. In some of the halls measurements were repeated using the procedures of the other teams to make it possible to separate the effects of different equipment and different procedures. The paper will present position-averaged results from the three teams and will discuss reasons for the differences observed. [Work partially supported by the Concert Hall Research Group.] 9:55 IAAA3. Compurisous of auditorium acoustics measurements as a function of ioc•tion in h•11s. John S. Bradley (M-27, IRC, In a measurement tour of nine U.S. concert halls measurements were made at 30 or more combinations of source and receiver position in each hall. Each of the three measurement teams (the University of Florida, the Danish Technical University, and the National Research Council of Canada) made parallel measurements of a number of modem room acoustics quantities using 2265 different equipment and measurement procedures. These results are compared on a sot-by-seat basis and the differences are explained in terms of earlier systematic studies of the effects of measurement procedure details. The measurement results were also used to examine the influence of different measurement equipment and measurement procedures on the within hall variations of the various acoustical quantities. [Work partially supported by the Concert Hall Research Group.] 10:20 laAA4. Effects of measurement equipment and procedure on IACC measurements. A series of binaural acoustical measurements were taken at several source locations and multiple receiver locations in eight concert halls using the Acoustical Research Instrumentation for Architectural Spaces (ARIAS) system and manikin developed at the University of Florida and the BRAM software system developed at NRC Canada with a B&K dummy head and torso. This paper will compare the results of room average data and several specific seat locations obtained from the two measurement systems with an analysis of the similarities and differences that arose. Correlations among various forms of IACC including IACC•r¾ IACC•a• IACCv, ith direct sound, and lACCwi,hou t direct so nd were studied. A comparison of binaural reflectograms for locations within each room were also made. Summary graphs showing ranges of each measurement within each of the rooms and discussion of similarities and differences among the groups of rooms will be presented. A binaural hearing manikin was constructed and then tested by comparing its bead-related transfer functions to those of a human subject. The manikin was used to record impulse responses in eight northeastern United States concert halls as part of the recent Concert Hall Research Group Study. The placement of the manikin's l/2-in. Bruel & Kjaer microphones varied between two locations: inside the head (truncating the auditory canal) and outside the head (20 mm from the canal opening). For most measurements, no statistically significant differences were found between octave band IACC values for the two microphone locations. The manikin's head-related transfer functions were measured in an anechoic chamber using both microphone positions and 324 source positions. Comparisons of reflectograms and head-related transfer functions show that the manikin's head and the human subject's head affect sound in similar ways.
doi:10.1121/1.406637 fatcat:qm3xseekvjgtpaucjdpbkm3o2y