Abstract：Diffuser sound scattering was predicted using the finite difference time domain (FDTD) method. There were no obvious differences in the diffusion coefficient when changing the distance between the diffuser and the receivers or source in the approximate far field. Then, FDTD was combined with the immune genetic algorithm to optimize the shape of a 6th order stepped sound diffuser which had better diffusion than the original diffuser. The sound scattering from the two diffusers became less diffuse when repeated over many periods. An aperiodic modulation method was used to combine a diffuser and its inverse diffuser using a binary code. Tests show that aperiodic modulated diffusers have better diffusion than periodic diffusers; however, this modulation cannot produce a flat diffusion coefficient curve, so the best diffusion is obtained by arranging the optimized stepped diffuser with the original diffuser together using a binary code.
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