Directional Loudspeaker System for a Big Hall

Abstract

ABSTRACTA wide band directional loudspeaker system with a nearly constant beam width of 30° in the vertical plane and 120° in the horizontal plane has been described here. Systems using straight line columns of speakers satisfy the directivity requirements over a limited frequency range. A uniform directivity over a wide range of frequency is achieved if radiators are arranged in a curve (arc of a circle). Vertical directivity was achieved by placing the seven speakers along a 60° arc of a circle of radius 5½ ft. and for horizontal directivity three such columns were placed in a 120° arc of a circle of radius 1¼ ft. The directivity remained substantially constant between 200 c/s. and 8 Kc/s. The system was tested in SWP hanger of Roorkee University having floor section of 166 × 142 ft. and metallic parabolic roof 34 ft. high. A considerable improvement in articulation index was achieved.