| Popis: |
This paper describes the procedure by which the acoustics of a church having severe focussed echoes was corrected by a sound‐reinforcing system employing passive narrow‐band LC networks. The church, seating 1600, is circular in planform, and its ceiling geometry approximates a paraboloid of revolution, with maximum height being 80 ft. Before correction, speech was heard with great difficulty, with the virtual sources appearing to move from point to point as the pastor changed his position on the rostrum. Sound from different members of the choir was focussed at different locations in the pews. Two concentric rings of double‐baffled loudspeakers were installed, with the speaker axes being vertical. Eighteen sections of narrow‐band networks were used in controlling room‐ring modes and feedback modes. |
