I bet you guys thought I was a little hard on Bob. lol. He does have a way with words. Take these for example.
"A problem with the 2-channel solutions suggested is that they all ignore the speaker/room interaction."
I see a couple of things here I don't quite get. First is the 2 channel solution recommended fixed the OP's problem. Philhoan has declared that he's getting the best sound he's ever heard. I say, we should just het him be so he can enjoy his system, but I guess I'm not the expert that you are. The second thing is that you're factually incorrect when you say that the 2 channel solutions recommended ignore room/speaker interrogation. The real beauty of the traditional 2 channel solution is that it allows you to keep room integration and electronics 2 separate entities. You're statement that we ignore it is just ignorance on your part. You don't need a home theater preamp to get a flat response. People have been doing without them for years.
"It's still a mystery to me how such a perfectionist group is so willing to accept imperfection when it comes to in room frequency response. At least Richard Vandersteen gets it."
I nearly wet my pants I laughed so hard when I read that. You don't even have Vandersteen speakers. I do, however. Several pairs. You could say I'm a big fan. Since you seem to be speaking for Richard when it comes to what he gets, and does not get, you may want to get your facts straight. The main feature that makes Vandersteen speakers special, it that they are time and phase correct. Its the main reason people buy them. If you use a HT preamp, or any type of room correction device, any adjustments you make, digital or analog, alters phase. Simply put, the answer to your mystery question, at least for Vandersteen speakers, is that it destroys what makes them special. And there's no need to take my word for it, call Vandersteen. He'll get on the phone and tell you himself, in a very mild mannered, low key tone of voice that he's famous for. The answer to your mystery question for other speakers, was already dealt with in the beginning of my post. We deal with the room separately. It's not ignored.