Where to start with room acoustics

The best sounding rooms are the ones that are treated. The LEDE (live end dead end) is a great way to go. Even just doing the wall behind your speakers can help immensely. This is something that can be done without any analysis and will definitely help. From there you can examine room modes, especially in the bass. This is one place it amazes me that so few people concern themselves with. If only they could hear a room treated and untreated. Nobody would leave their room untreated unless forced to for some reason, usually female.

LEDE is treated on the side of the system leaving the rest of the room live. Very common among very knowledgeable people as in recording studios or the best audio setups. There's lots of information on it. As far as bass is concerned the largest problem is of course corners but tube traps are necessary to tame bass, foam alone won't do it. The traps may be set in different areas of the room depending of course on your room. Check out Jon Risch's DIY site. Lots of good info there including how to make your own bass traps for alot less money and they work great. Good luck. You'll be glad you treated your room. Unless it is a very dead room I'd try some treatment behind the system.