Three-dimensional Resonance Control Based on Spatial Wave Synthesis with Parametric Array Loudspeaker
* Presenting author
A parametric array loudspeaker (PAL) realizes a sharper directivity utilizing the demodulation of intense amplitude modulated (AM) wave. The demodulation is modeled as spatial sound sources generated with the demodulated audible sound in the acoustic beam. Spatial sound sources form resonance and anti-resonance positions in the acoustic beam because of the interference between spatial sound sources. Thus, the sound pressure level (SPL) of the PAL is reduced at the anti-resonance position. However, it suggests that resonance positions might be reformed by spatial wave synthesis with phased array processing. Therefore, we propose three-dimensional resonance control based on spatial wave synthesis with the PAL. In this paper, we employ the PAL consists of line-type PALs corresponding to column. The PAL can apply different delay filters to each column. The proposed method designs inverse filters with a multichannel adaptive algorithm as delay filters for line-type PALs under the constraint condition that the SPL is maximized by spatial wave synthesis at the target position. The proposed method can improve the SPL at the target position by applying the designed filters to each column. Finally, we confirmed the effectiveness of the proposed method through evaluation experiments.