Realization of an omnidirectional source of sound using parametric loudspeakers.

Parametric loudspeakers are often used in beam forming applications where a high directivity is required. Withal, in this paper it is proposed to use such devices to build an omnidirectional source of sound. An initial prototype, the omnidirectional parametric loudspeaker (OPL), consisting of a sphere with hundreds of ultrasonic transducers placed on it has been constructed.

Directivity control and efficiency of parametric loudspeakers with horns.

This manuscript presents some recent results on directivity control and efficiency of parametric loudspeakers utilizing horns. Horns act both like an acoustic transformer and a directivity control method. An experimental device has been built and measurements have revealed that the horn has a clear influence on the audible sound levels and directivity of the parametric loudspeakers.