Directional Loudspeakers Using Sound Beams

Abstract

The relative merits of two directional loudspeakers intended for localized sound-field production, each driven by a single, compact transducer, are considered. They are intended for applications in which audio is required by listeners congregated in a small region of an otherwise reverberant or noisy environment, such as multimedia venues involving kiosks, museum displays, theme parks, and game centers. The loudspeakers are end-fire line arrays consisting of 1) a ducted point source employing a single compression driver, in which the point sources are at the open ends of tubes of unequal length connected to a common manifold and 2) a parametric acoustic source produced by an intense beam of ultrasound. The directionality, frequency response, and audio output of the arrays are compared by measurement and simulation.