[bpape]

For EQ, I wouldn't have anything but a parametric. Even a 1/12th or 1/24th octave is a guessing game to try to get lucky and match what you need to their band centers - not to mention Q.

If the null is all around the room, answer me this. Is it all through the room standing up or sitting down or both?

If it's everywhere in the room, it's almost got to be something in the setup. Quite honestly, looking at your graphs, the FR is actually pretty good. You're within about a total of 5db up to 100Hz except for a small bump about 38Hz.

Realistically, if you can get +/-4db in a room - especially without a sub - you're doing very well. I personally wouldn't mess with it. Target decay time will depend on the room size.

Bryan