Abstract: A two-dimensional sound diffusor is composed of a plurality of wells defined by a matrix of projecting elements. The wells, which have different depths and widths, are arranged in a repeating pattern. The boundaries of the wells and of the repeating pattern are defined by projections arranged on a base. The ends of the projections extend away from the base, terminating in an inclined face which is inclined relative to the base by an angle of 10.degree.. The incline may be rotated from one projection to the next, on a plane parallel to the base of the unit by 90.degree. or 180.degree.. This arrangement produces two dimensional sound diffusion.