I am building a dedicated home theater room in my basement and am trying to make sure it sounds great, and make my wife happy by having it look great. Would making the rear wall a stacked stone wall help to act as a diffuser, or would it be a disaster and hurt the audio quality? I am a newb trying to learn about all the theory for best sound and put it not practice.
Stone could possibly be used as a diffuser, but you'd have to design it as a specific pattern. And the surface depth / distance between the front-most and inset stones needs to be at least 3 to 6 inches. This video explains the basics:
If you're really serious about making your space acoustically excellent, a better approach would be to build that rear wall from thick rigid fiberglass for bass trapping, then apply faux stone made from lightweight Styrofoam. That would diffuse mid and high frequencies and absorb bass frequencies, which is exactly what's needed for a rear wall.
+1. Our church has a large stone wall at the front. It's a lousy diffusor. It's also curved perfectly so the smallest whisper out in the foyer can be heard quite well right where the preacher stands to give his opening announcements. This leads to him waiting for sounds to die out, or until the doors at the back are closed, even though most of the congregation doesn't hear anything and wonder why he's just standing there.
Ethan's site has a wealth of information and very nice tutorials. It is well worth your time to read through his material and ask questions. A few hours time will save you much sonic aggravation.
"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley