There is a pressing need for effective acoustic diffusion treatment with a minimal thickness profile, in particular for the retrofitting of orchestra pits. Sound can reach dangerously high levels in these environments, but highly absorptive boundaries in an orchestra pit are usually not desirable, among other reasons because it compromises ensemble conditions. Implementing diffusion retroactively would be difficult, as there is often little space for such treatment. Acoustic metadiffusers offer a promising solution to this, but lack real-world testing and scalable production. This paper describes this knowledge gap, with a view to ultimately creating a target sound field optimised for musician's performance and safety. This would be made possible by the inherent flexibility of metamaterial design concepts, pointing towards the future development of metadiffusers, specifically as regards to their practical implementation. The aim is to be able to soon fill this knowledge gap, contributing to advancing the understanding of acoustic diffusion treatments. An early stage study will be the assessment of the differences between near and far fields produced by such scattering surfaces in order to be sure of the suitability of ultra thin diffusers for use as retrofitted treatment.