Diffusers are used to disperse sounds. In small rooms, such as studios, they smear early arriving reflections which otherwise could cause distortion. In larger spaces, such as auditoria, concert halls and theatres, they might be used to form stage or audience canopies to evenly distribute sound around the space. In the last few decades, many new types of diffusers have been developed, but still crucial aspects need researching. For instance, subjective testing is needed to evaluate the true perceptual worth of diffusers - such a phd could expand to develop binaural coloration measures which currently don't work well. Other doctorates could explore prediction and measurement methods for diffusers, for instance the former might research time domain methods while the latter might explore in-situ measurement techniques.