Are there any attributes of your room that you think make it so abysmal?
Other than the H, L, W dimension natural frequencies and especially not wanting them all to be the same, I don't know much about what makes a room good or bad for bass response.
Well, for one thing, it's not a room in the classic sense. We have one of those contemporary open floor plan homes. The family room, where the system is, is the left third of an open space that's about 45x21 or so. The part that makes up the family room has an 18 foot high vaulted ceiling, while the rest of the space has a nine foot ceiling. Above the area with the nine foot ceiling is a loft open to the family room, with an eight foot ceiling. I've guessed that the loft is causing some of the weirdness.
The way the main speakers are set up they are about four feet out from the back wall, which is mostly glass, the left speaker is about three feet from the side wall, but the right speaker is mostly in open space; there's only a one foot deep corner on the right side. In these positions the Salon2s are wonderfully flat from about 500Hz onward, with a slight dip at 1.5KHz, but below 500Hz it's a war zone. Unassisted there's a strong room mode at slightly above 50Hz, with suck-outs above and below that frequency.
In a better room I'm not convinced the Salon 2s would need subs for music at all. In my room the sub seems there mostly as a fill-in, and as another bass source to smooth response overall. (I'm currently running the Revels full range.) The output from the sub is really quite modest, but the effect of switching it in and out is very noticeable. There must be quite an interesting interference effect going on between the bass sources. One of my friends thinks it's eerie. I told him to borrow his son's high school physics text.