Long, narrow rooms with high ceilings are particularly difficult spaces for which to design sound-reinforcement systems. Rooms such as these typically require a combination of short-throw ( low Q ) loudspeaker components configured as a large, central cluster to provide uniform coverage over the seating space. Unfortunately many such rooms, in particular those of A-frame design, do not have adequate provisions for mounting a large cluster of loudspeaker components in an aesthetically pleasing fashion. A possible alternative for such a venue is described. In place of a central cluster with a large vertical dimension, we propose using an ensemble of horizontally mounted, electronically (phase-delay) steered line-source arrays. Each line source has a Q commensurate with the distance it must throw and the area it must cover. Shading is employed to minimize side-lobe energy as well as to help stabilize coverage patterns. Many desirable properties associated with a central cluster system, such as minimum energy directed toward the speaking position, stable coverage patterns, and preservation of locality of reference, apply to the proposed alternative described. Advances in signal-processing hardware technology help make a sound-reinforcement system design based on this approach both technically and economically feasible.
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