Directional loudspeakers using sound beams

The relative merits of two directional loudspeakers intended for localized sound-field production, each driven by a single, compact transducer, are co nsidered. They are intended for applications in which audio is required by listeners congregated in a small region of an otherwise reverberant or nois y environment, such as multimedia venues involving kiosks, museum displays, theme parks, and game centers. The loudspeakers are end-fire line arrays c onsisting 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 lengt h connected to a common manifold and 2) a parametric acoustic source produc ed by an intense beam of ultrasound. The directionality, frequency response , and audio output of the arrays are compared by measurement and simulation .