2aAA7. Predicted and actual intelligibility-rating values produced by a unique church speech reinforcement system.

Session: Tuesday Morning, June 17

Author: Dan Clayton
Location: 720 Fort Washington Ave., Apt. 1R, New York, NY 10040
Author: L. Gerald Marshall
Location: KMK Assoc.


A new speech-reinforcement system was included in the 1996--97 reconstruction of historic St. James's Church in Richmond, VA, following a major fire in 1994. Intelligibility of the spoken word was of primary importance to the congregation, yet they also wished to improve the already lively sanctuary acoustics for enhancement of the choral and organ music so integral to traditional Anglican worship. Considerations of superior electro-acoustic performance and sensitivity to appearance in this architecturally significant and reverberant room overcame the usual client preoccupation with cost, and led to the selection of a system incorporating digitally controlled, steerable-pattern, vertical-line-source loudspeakers. Evaluations of system performance during design were based on both ``drawing-board'' calculations and computer modeling with a sound system design program, and involved three speech-intelligibility predictors: C[inf 50], STI (RASTI), and %Alcons. Comparisons of the predicted intelligibility ratings are made with post-completion measured ratings. Results of effective-directivity (Q[inf ds]) and frequency-response measurements are included.

ASA 133rd meeting - Penn State, June 1997