Reverberation steering and listening area expansion on 3-D sound field reproduction with parametric array loudspeaker

Abstract

Recently, technologies for reproducing a 3dimensional sound field are required for providing highly realistic sensations. Therefore, we previously proposed a system with multiple parametric array loudspeakers (PAL). PALs can design sound images on walls, ceilings, and floors by using the higher directivity of ultrasound. Thus, the proposed system can easily present incoming sound from various directions. However, it is difficult to provide a realistic sensation depending on the reverberation time. In addition, the listening area of one PAL is small. In this paper, we therefore propose two approaches for overcoming these problems. First, we propose reverberation steering with indirect electrodynamic loudspeakers and PALs. We also attempt to expand the listening area of the sound image with a curved-type PAL. As a result of evaluation experiments for each proposed approach, we could confirm the effectiveness of each approach.

An overview of directivity control methods of the parametric array loudspeaker

“…In the three-dimensional sound reproduction, a convex PAL as shown in Fig. 3(d) outperformed the concave PAL in terms of the size of the sweet spot [37]. Besides changing the array configuration of the PAL, the directivity of the PAL was also narrowed when a horn was attached to the PAL, which was shown in Fig.…”