Acoustical characteristics of a 360-degree surround hall

Abstract

Boettcher Hall in Denver is a large multipurpose hall with audience seating completely surrounding the stage and has been described as a 360-deg surround hall. Extensive acoustical measurements were carried out to evaluate the characteristics of this hall configuration and to compare it to other halls of more conventional design. Impulse response measurements were made for the 45 combinations of three on-stage source positions and 15 receiver positions distributed throughout the audience seating area. The setup of the hall was representative of a typical unoccupied concert configuration. Measured parameters included octave band values of: reverberation times, early decay times, relative sound levels, and early/late sound ratios. Various measures of spatial impression were also measured including: lateral energy fractions, inter-aural cross correlations, and the newly proposed measure of listener envelopment, the late lateral sound level. Hall average values as well as the spatial variation of acoustical measures are compared to data obtained from a number of other halls. [Work supported by the Concert Hall Research Group.]