Please remember that if you plan to use it as an absorber for room treatment you want a minimum thickness of 3". I see people think rugs etc will work but it's not very effective except at very high frequencies. 4-6" is much better. This is due to the fact that sound travels in waves that have lengths. If your rug is only 3/4" thick then it will only help the upper treble. If it's 4" thick it will help down into the midrange and make a much better improvement.
Whatever you do you should at least try a couple sheets of some thick foam. Once you find out how much it helps you'll be wondering why you didn't do it a long time ago, I know I did.
If I had it to do over again I'd use rigid fiberglass panels with a fabric covering. Presently I have 3" and 4" wedge foam covering 5' out on both walls and ceiling around my system as well as the entire wall behind it. It is very effective and the sonic presentation in here is outstanding but it would have looked better using the rigid fiberglass idea and probably not have cost much more. This much acoustic wedge foam I probably spent a good 600 dollars or more on.
