The SoundPlank is the basic tool for church acoustics. It is a 2” sound panel that is long and narrow and usually matched in color and texture to the wall paint so that it becomes a architectural geometric feature of the room. It comes with a built in reflector strip to keep from over deadening the room. It is used in a criss-cross grid pattern on the ceiling and in a vertical spaced pattern on the walls. Its absorption coefficient is 150%, NRC 1.05, which means it only has to cover about half the amount of wall or ceiling surface as flat panels do. Because of its high aspect ratio it produces directional acoustic properties, in which some sounds are barely attenuated and yet others are heavily attenuated. One of its most surprising features is that it provides not only absorption but powerful diffusion as well.