Systems, apparatuses, and methods for diffusing sound can comprise a sound or acoustic diffuser or a plurality of sound or acoustic diffusers. The acoustic diffuser can be provided as a 90 degree segment to fit into an inside corner, and a plurality of 90 degree segments can be arranged relative to each other to effectively provide 180 degree, 270 degree, or 360 degree contiguous acoustic diffusers, where the 180 degree acoustic diffuser can be arranged relative to a flat wall, and the 270 degree acoustic diffuser can be arranged relative to an outside corner. Furthermore, each 90 degree segment, or contiguous combination of segments, can have vertically stacked thereon (or be vertically stacked on) another segment of same construction, in freestanding fashion.