An optimization method has been used to design unbaffled and baffled curved diffusers for performance spaces. The design method requires single parameters to characterize the quality of diffusion produced. A parameter based on the standard deviation function has been refined and used for the unbaffled surfaces. For the baffled diffusers a new method was used which is based on the difference in scattering over the specular zone when the diffuser is added to the baffle. The unbaffled new diffusers match or outperform standard curved based on the arc of a circle. In some cases the arc of a circle is the best solution available. This occurs when a near semicircle is within the allowed geometry. Tests also examined forming unbaffled modular diffusers from many periods of identical curved diffusers. Similar results regarding semicircle shapes were found. Signs of lobing for many periods of the curved diffusers were seen. For baffled diffusers the new optimized surfaces always had a better performance than the arc of a circle, reducing the scattered pressure within the specular zone by 4-dB on average. Measurements confirmed that better performance was achieved for an optimized baffled surface, compared to the standard arc of a circle.
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