CA,
> I could use some help treating this room. <
This is a deep subject, and a complete answer requires far more than will fit into a single reply here. The short version is:
* Broadband (not tuned) bass traps in as many corners as you can manage, including the wall-ceiling corners.
* Mid/high frequency absorption at the first reflection points on the side walls and ceiling.
* Some additional amount of mid/high absorption on any large areas of bare parallel surfaces, such as opposing walls or the ceiling if the floor is reflective.
For the complete story see my Acoustics FAQ:
www.ethanwiner.com/acoustics.htmlYou may want to do everything listed above, but that's the goal anyway.
--Ethan