1. A sound field mapping method comprising: generating electrical signals in response to sound in the sound field; applying the generated electrical signals to a spatial angle and diffusivity information extraction module operable to extract spatial angle and diffusivity information from the electrical signals; and applying the extracted spatial angle and diffusivity information to a mapping module; using the mapping module to map the spatial angle and diffusivity information for representation in the form of a Riemann sphere, wherein spatial angle varies longitudinally and diffusivity varies latitudinally along the sphere.