A Designing Method of Multi-Channel Ultrasound Source Signals for Presenting Private Sound Field with Parametric Mixing in Air

We aim to generate a private and personalized audible sound field spot in an intersection region of two parametric sound beams. We design driving waveforms of the parametric sound sources so that the secondary sound source waveform produced by self-demodulation after nonlinear mixing in the intersection region is as close as possible to the desired one, whereas the produced secondary sound is indistinct outside this region. Unlike conventional parametric-array-based methods, our method aims to achieve the three-dimensional spatial selectivity of comprehensible audio presentation. In this study, we propose two different design method of driving signals of the sources. We qualitatively assessed the auditory qualities of the presented audible sound with our method by primitive subjective observations.