Development of omnidirectional audible sound source using facing ultrasonic transducer arrays driven at different frequencies

Abstract We present an audible sound source with omnidirectional patterns in the horizontal plane using facing ultrasonic transducer arrays driven at different frequencies. In this experiment, ultrasonic transducer arrays were placed face-to-face on a straight line. They radiated sound with different ultrasonic frequencies from each side. Through elementary examination, we realized directionality close to omnidirectional in the horizontal plane using ultrasonic transducer arrays arranged in a circular shape, which is rotationally symmetric in all degrees. In addition, using an acoustic camera, a sound source region was found to be generated between the arrays.