John Bassett

The acoustic environment of an auditorium stage can enhance the ability of musicians or actors to hear each other clearly. This is assessed through a set of parameters called 'stage support'. Stage support parameters are conventionally measured using an omnidirectional source and microphone separated by 1 m on the stage. Various stage support parameters are derived from energy ratios of the direct and reflected (or reverberant) sound in the impulse response from source to microphone. The present paper examines the possibility of assessing the directional characteristics of the reflected soundfield by using a multidirectional microphone. Measurements were made in the Sydney Theatre Company's 'Sydney Theatre' with and without a stage set. The microphone used allows first order spherical harmonic decomposition of the soundfield, which was transformed to cardioid components for orthogonal directions (upstage, downstage, left, right, up and down), as well as for horizontal rotations of the cardioid microphone. These were used to calculate directional stage support values. Results demonstrate the potential of this simple extension of standard stage support measurement by showing the acoustical effect of the set.

Opera performance conveys both visual and auditory information to an audience, and so opera theaters should be evaluated in both domains. This study investigates the effect of static visual and auditory cues on seat preference in an opera theater. Acoustical parameters were measured and visibility was analyzed for nine seats. Subjective assessments for visual-only, auditory-only, and auditory-visual preferences for these seat positions were made through paired-comparison tests. In the cases of visual-only and auditory-only subjective evaluations, preference judgment tests on a rating scale were also employed. Visual stimuli were based on still photographs, and auditory stimuli were based on binaural impulse responses convolved with a solo tenor recording. For the visual-only experiment, preference is predicted well by measurements taken related to the angle of seats from the theater midline at the center of the stage, the size of the photographed stage view, the visual obstruction, and the distance from the stage. Sound pressure level was the dominant predictor of auditory preference in the auditory-only experiment. In the cross-modal experiments, both auditory and visual preferences were shown to contribute to overall impression, but auditory cues were more influential than the static visual cues. The results show that both a positive visual-only or a positive auditory-only evaluations positively contribute to the assessments of seat quality.

The Sydney Opera House Trust is considering making changes to its Concert Hall. Prior to any alteration, the Acoustics group at the University of Sydney has sought to document the hall. The main measurements were made for 48 receiver locations and 6 source locations, using omnidirectional measurement microphones, B-format (Soundfield) microphones and dummy head microphones in every receiver position. The measurements included impulse responses, anechoic music recordings, and recordings of a calibrated sound power source. Results documented by previous practitioners and researchers are described and comparison is made with the recent results.