My living/listening room has a ceiling that slopes from 9' to 17' feet at its apex with sidewalls on the left about 4 feet, and about 14 feet from the right speaker, plus a hardwood floor. Oy vey - a pretty difficult room to get a grip on for any speaker.
In the virtual systems section here I've posted a few photos of my setup. The speakers are positioned about 8 feet apart. I listen from about 10 feet away. They are positioned 8 inches from the rear wall. (I have a stick with markings on it, a "mod" I created in mind after shuffling my Maggies, Von Schweikerts, Totem Hawks, Dahlquist DQ-10's around. Got tired of looking for the measuring tape.)
To wit, my experiments with the eq of the 3.5's in and out and/or with the 40hz setting have borne out leaving it in place is the best FMHE.
(for my humble ears) I also noticed that the imaging had suffered when it was entirely removed. Jim knew more about this stuff than I do, so I'm adhering to his philosophy and architectural theories, leaving it in the chain.
One of of the reasons I so enjoy these lies in not having to bother with a sub. More wires, more power, more space.... As I've mentioned in earlier posts my listening level is conservative. I have never pushed these to "concert" levels, and I never will. Just toss in Ginger Baker's "Cyril Davis" off of the album "Why?" at a modest level and see why these speakers can still impress, if not astound.