Personal sound system design for mobile phone, monitor, and television set; Feasibility study

Abstract

Having a personal sound system that does not need to use an earphone or any wire connected microphone would have great interest and potential impact on the associated industries. A device that uses nonlinear characteristics of high intensity ultrasonic sound, such as a parametric array, enables us to localize the sound on any position we want. However, it requires a fairly significant amount of power consumption. Therefore, the mobile phone or note book computer system cannot accept this type of device. Instead, we have attempted to use a line array speaker system to localize the sound in our listening zone. It is known that sound pressure or intensity can be well focused in the zone of interest: For example, see [J.‐W. Choi, Y.‐H. Kim, J. Acoust. Soc. Am. 111 (2002)]. We applied the method to see the possibility to make a good bright zone around the human head or ears. Depending on the size of the zone and array parameters, for example, array size, speaker spacing, frequency characteristics of the speakers, the quality of the bright zone is changed. The quality means the ratio of sound energy between the bright and dark zone, regarded as acoustic contrast, analogous with what we use for an optical device.