title: Realization of an omnidirectional source of sound using parametric loudspeakers.
abstract: 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. The OPL emits audible sound thanks to the parametric acoustic array phenomenon, and the close proximity and the large number of transducers results in the generation of a highly omnidirectional sound field. Comparisons with conventional dodecahedron loudspeakers have been made in terms of directivity, frequency response, and in applications such as the generation of diffuse acoustic fields in reverberant chambers. The OPL prototype has performed better than the conventional loudspeaker especially for frequencies higher than 500 Hz, its main drawback being the difficulty to generate intense pressure levels at low frequencies.
authors: GTM-Grup de recerca en Tecnologies Mèdia, La Salle, Universitat Ramon Llull, C/Quatre Camins 2, 08022 Barcelona, Catalonia, Spain.
authors: Umut
authors: U
authors: Sayin
authors: Pere
authors: P
authors: Artís
authors: Oriol
authors: O
authors: Guasch
mesh_terms: D000669:Amplifiers, Electronic; D004867:Equipment Design; D009038:Motion; D011312:Pressure; D012815:Signal Processing, Computer-Assisted; D013016:Sound; D013018:Sound Spectrography; D014160:Transducers, Pressure; D014465:Ultrasonics / Q000295:instrumentation*; D014732:Vibration