I tried to take room measurements and treat my room, but without experience in acoustics the measurements didn't mean much, even after reading Alton Everest's book and visiting many websites. I finally talked with Rives (they designed a plan that I used), RPG and RealTraps. Then I went through two stages of adding room treatments. The first stage got the room to where Blues, Jazz and Rock sounded good. In the second phase I added more bass absorption along the front wall-ceiling and back wall-ceiling and diffusion on the ceiling. Now I enjoy listening to classical music in addition to the other music. The change is amazing.
After I added the room treatments in the first phase, I had my room professionally measured by an engineer using acoustical software. The engineer created a virtual room, added the treatments and got the hypothetical reverb times. Then we measured the room to validate the calculated results. The software was spot on! It also showed that I need to move my CD rack to get better balanced imaging. In a couple of weeks I'm going to have my room re-measured using waterfall plots to see the final results.