These devices reduce the intensity of sound by scattering it over an expanded area, rather than eliminating the sound reflections as an absorber would. Traditional spatial diffusers, such as the polycylindrical (barrel) shapes also double as low frequency traps. Temporal diffusers, such as binary arrays and quadratics, scatter sound in a manner similar to diffraction of light, where the timing of reflections from an uneven surface of varying depths causes interference which spreads the sound.
Diffusion in simple terms is the scattering of sound energy. When sound bounces off hard flat surfaces, the energy remains very much intact yielding discrete echoes. These echoes will produce destructive effects like comb filtering, standing waves and flutter echoes which degrade speech intelligibility and music clarity. Installing sound diffusers can deal with this problem. Diffusers interrupt discrete echoes by scattering or diffusing sound energy over a wide area without removing it from the room. This maintains sound clarity and improves speech intelligibility.