Combining shape and a hard, high-impact surface, the Ultimate Acoustics UA-PYD Pyramid Diffusors diffuse sound evenly across the room to control âflutter & echoâ effects. The UA-PYD is a great choice for tracking spaces, control rooms or any environment in need of controlling sound reflections. The Pyramid Diffusors help maintain a âliveâ sound and lend a sense of dimension to any room.