Since ancient times, churches, theaters, and other architectural structures have used periodic wall shapes and structures. These wall shapes have been used as acoustic diffusers that scatter sound and homogenize the sound field. Wall-integrated diffusers lead to fixed reflection patterns, limiting acoustic flexibility for multipurpose use (e.g., orchestra, chamber music, speech). Therefore, we propose an adjustable diffuser that can be used for multiple purposes in the same room. In this study, we focus on the origami structure with plane filling and spiral fold lines. For each sample, the degree of folding and the fineness of the shape were varied and analyzed numerically. As a result, it was confirmed that these parameters affect the acoustic diffusion characteristics. In particular, the coarser the shape, the higher the scattering coefficient at low frequencies. In addition, the deeper the fold, the more uneven the surface became, and thus the more diverse the sound scattering became.
Sakino et al. (Wed,) studied this question.