13 by 13 is tough since the same frequencies are reinforced and cancelled by two of your three dimensions. If you can move the system to a different room, you'll definately be better off. If you have 8 foot ceilings, you will get artificially strong bass at 44, 87, 130, 174, 217, and 261 Hz with big gaps inbetween. Bass below 44 Hz will be hard to come by. That's tough to correct. You may need to either get a very narrow bandwidth equalizer or go to the Rives website and look into that equipment.
"do it yourself" acoustics
I have a 13'x13' room. In this room, I have Vandersteen 3a speakers driven by a 100wpc Aria amp through a CJ Art Pre. Music is despenced through a CJ DV-2B Disk Player. That said, I am looking for "do it yourself" ideas for dampning this chamber of echos. Listener's fatague is cutting into my listening time. Please diregard poor spelling. Many thanks. Steve