Directional sound radiation system using a large planar diaphragm incorporating multiple vibrators

This paper aims to construct a system that produces directional sound radiation. Directional sound is intrinsically radiated from a vibrating resonant body of such instrument as a violin. The directivity is said to give the sound a realistic and spatial effect. To reproduce a sound with such directivity, we propose a method that uses multiple vibrators to artificially induce bending vibrations on a large planar diaphragm. As the first step of this study, we constructed a prototype system and demonstrated that (i) the bending vibration of the diaphragm is controllable by adjusting accelerated vibrations and (ii) the radiated sound obtains directivity as a specified condition by a user using the algorithm we proposed. This directivity of the radiated sound was obvious enough for humans to perceive.