On Control of Radiation Directivity with Passive Sources for Auditory Signals

Abstract

This paper describes a study on control of radiation directivity with passive sources for auditory signals. A model analyzed here consists of a primary point source and one or two passive point sources when the primary source radiates a pure tone with a constant volume velocity. The passive sources respond acoustically to the applied sound pressure radiated from other sources in same frequency. The relation between the volume velocities of the passive sources and directivity is analitically obtained. The limitations on the amplitudes and phases of the passive sources are taken into consideration. The effects of the location and the acoustic impedance of the passive sources on the front-to-back ratio and gain are discussed in detaio.