This article argues that despite the rich possibilities inherent in current sound diffusion and spatialisation systems, none of the current systems can fully mimic the spatial characteristics of natural sound systems and we are still a long way from having achieved performance that comes close to that of a natural soundscape. By examining the nature of our spatial hearing and the history of sound spatialisation systems, this article attempts to map possible routes, taking us closer to full "reality equivalent" sound diffusion systems.