Hotmailjbc,
When you say you have roomtunes in the corners of the room, are you referring to the Michael Green corner tunes -- that is, the triangle "pillows" that go in corners?
If so, what is your experience with them as far as how much of an improvement they make?
I have some absorption panels and diffusion, and they make a huge difference in my room. For example, if I were to take any of the treatments out of the room, it would be noticeable (for the worse). Do the corner tunes make much of a difference? Is it mainly in upper frequencies?