I've taken lots of measurements with carpet and just beginning to do the same with the wood flooring. I was shocked to hear the bass change so drastically. I found that since my theater room is on the 2nd floor, the carpet was acting like a flexible membrane as opposed to the stiffer wood floor which seems to be exciting the problematic room modes more. I had to reposition 1 of my subs 2 feet and really tweak it out to get the system to sound good and free of boom. I put a large throw rug at the first reflection point and plan on putting a smaller additional one under my drum kit to help reduce the now added slap echo in the right front corner of my room.
Overall the stereo image is wider and the room sounds more natural. Despite the few setbacks, I am confident I am moving in the right direction.