Thanks for all of your insight, tips, and knowledge. I've set up a couple of small mixing/control rooms now. The first was in a rental space, so my treatment options were limited, and I struggled with the lower frequencies the most. The second is in my current home, and I had the freedom to get much more creative, with the treatment. The room size is roughly 12' x 15', with an 8' ceiling. Hardwood floors, 2-GIK Monster bass traps [8" thick] at the rear wall, 6-GIK 244 bass traps [5" thick] at the first-reflection points to the sides, and the ceiling. I did this after analyzing my room with the Sonarworks Speaker Calibration system. It is a work in progress to get any room to sound good! So, after many tests and calibrations, and a few months of working with this setup, I upgraded my monitors, but more importantly purchased a sub, to help balance out the low-frequency curve my room was having. I didn't think I would need one for this size room, but once it was calibrated, I was shocked at the difference. And bouncing between headphones, monitors, and even a quick car test, are now much closer than before.
* I wanted to quickly mention, that although I spent a little extra money to purchase professionally made traps, I also spent quite a bit of time searching the classifieds, Craigslist, and the used gear forums to pick up extra foam wedges, corner traps, and some mini fusors. It was well worth the effort and patience, as I saved hundreds of dollars off the retail price by going with some used foam. People move, and or decide to sell gear all of the time, so keep your eyes open if you are just starting out!
I do have one questions for you regarding soundboard. A colleague of mine put up soundboard over the drywall on 100% of the side walls, leaving the ceiling and hardwood floor alone. He covered the soundboard with an inexpensive fabric, and I have to say, I was impressed with how much it decreased the reverberation in the room. There was still some high-frequency ring from the ceiling and floor (which was later taken care of with additional absorption, and diffusion), but the decay time overall in the room was drastically improved. Do you or would you ever recommend using soundboard in certain room situations? I believe it was pretty inexpensive, and roughly 3/4" thick.
Thanks again for all of your time and knowledge on the subject,