In the world of acoustic room treatment, you can do one of two things: You can absorb energy or you can diffuse energy. The familiar acoustic absorber converts the sound vibration energy into heat and prevents it from reaching a hard surface and reflecting back into the room.

Diffusers on the other hand are designed to break up acoustic energy and reflect it back into a room in a random pattern. The intention is to reflect a diffused ambient sound field as opposed to just absorbing acoustic energy. The benefits of diffusion are improved imaging, a larger listening “sweet spot” area, and general “lively” room ambiance. A well balanced room will combine both absorption and diffusion.

Normally, a diffuser is placed on the rear wall of the home theater so sound energy from the front loudspeakers may be diffused and reflected toward the listening position. Rear wall diffusion creates a nice sense of ambience making a small room sound like a larger space. Diffusers may also be located on the side walls between the loudspeaker and listening position. Diffusing the early reflections before they reach the listening position maintains the “air” in the sound without giving up dialog intelligibility.

How much diffusion do you need?
A good rule of thumb for rear wall diffusion is to cover the width of the listening position. In other words, if the seating area is six feet wide, diffusers along the rear wall should cover that width.

For the side walls, designers use vectors to find nd critical wall positions where the diffuser will intercept and break up primary early reflections before they head to the listening position. Check out the Early Refl ections Smart Sheet to learn how you can use a mirror to fi nd locations for side wall diffusion. Razorblade Quadratic Diffuser

Primacoustic manufactures the Razorblade Quadratic Diffuser. The Razorblade is 24” wide, 48” tall and 10” deep. It contains wells of various depth. The depth of the wells are tuned for a wide bandwidth of frequencies and the Razorblade can effectively diffuse sound energy from 400Hz and up. Razorblade diffusers are designed to be ganged together to increase the size of the diffuse fi eld. The Primacoustic Razorblade can be painted to match your decor.

For more information on how the Razorblade works check out the "interperting impluse response test result" application note.

Soft Diffusion
A great low-cost alternative to the Razorblade is to employ a system we call Soft Diffusion™. Soft-diffusion works by allowing random sound energy to reflect back into the room and is achieved by staggered mounting 12” x 12” Broadway Scatter Blocks. It is a very effective approach for the rear and side walls as well as general treatment of your home theater. We recommend 2” thick Broadway Scatter Blocks to effectively manage mid-range and treble frequencies. [read more about Soft-diffusion.]