How to Build a Diffuser: A diffuser is a great way to control reflections in a room and make your room sound flatter. If your room is on the “dead” side, diffusers may be more suitable than adding absorptive sound control. Diffusers are often placed on the back wall behind the engineer’s head. They can also be placed in the studio to help tighten up a room, reduce flutter echo, and control reflections. Here’s a good way to make a diffuser using a proven formula.