I am not trying to downplay the good effects of proper room treatment but I think that a lot of audiophiles do this to try to correct a poor digital front end. If you are not using a D/A converter I would try that before spending extra cash on rebuilding walls. You can buy an adcom gda-600 used for under $350 and start off with a 75ohm video cable as the digital innerconnect. If your cd player does not have a digital output you can also get that used for cheap. If your cd player is throwing away digital information you can NEVER get it back. Also, many cd players blend the lower bass to mono and that in itself will muddy up a room's sound.
room acoustics
I'm tearing out the panelled walls in my listening room and have the opportunity to design some acoustic treatment into the room as I refinish it. My reason for posting is to seek advice from those who have travelled this path before. The only plan I have so far is to make the amplifier/speaker wall absorptive (via several inches of insulation). I'm most concerned about the effects of the sliding-glass door and the off-center fireplace. A description of the room follows. The room is 12 by 19 feet. (speakers are on the short wall.) The leftmost 3/4 of the opposite wall is a brick fireplace. (the other quarter is the entrance to the kitchen ... no door) The left wall also contains a sliding glass door. The right wall is uninterrupted until you reach the rear of the room, where there is another passageway ... 90-degrees to the aforementioned Speakers are full-range, and the listening position will be out in the middle of the room. Any help is appreciated. David