A constant-directivity defined-coverage loudspeaker horn that approximately covers a flat rectangular area from an oblique angle is described. The horn compensates roughly for the inverse rolloff of sound pressure in the forward-backward direction by varying the horizontal coverage as a function of the elevation angle. The horizontal coverage angle of the horn at the 6-db-down points at each elevation angle is matched to the required horizontal angle of the rectangular area as seen by the horn. Measurements on a prototype horn which covers a two by three unit area from a point one unit above the center of the narrow end are shown. This horn roughly covers a 70-deg vertical angle with the horizontal coverage smoothly changing from 90 deg at 0-deg elevation (straight down) to 38 deg at 70-deg elevation.
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