Analysis of the sound field in circular spaces using small scale models and parallel phase-shift interferometry

Abstract

In acoustic design, the use of circular spaces is generally avoided. This is because these spaces present several acoustic problems, for example, “whispering gallery,” and low diffusivity of sound. These room acoustic problems have generally been dealt with by installing diffusers on walls. In this study, we designed the acoustics of the circular space by applying diffusers based on primitive roots and analyze the sound field. These diffusers were proposed by Schroeder and take advantage of the randomness of the numerical sequence generated from primitive roots. We designed several small circular models attached the diffusers and printed them with a 3D printer. The sound field in the models were measured and visualized using parallel phase-shifting interferometry, one of the optical sound measurement methods. As a result, “whispering gallery” phenomenon was improved, and focal points were less likely to occur by the application of diffusers based on primitive roots.