If your speakers have a neutral response, the only thing Audyssey can really do for you is take down some of the peaks in the bass range. You will want to measure the room response at your listening position yourself. I recommend taking a measurement, running Audyssey, taking a post audyssey measurement, and comparing them. My guess is, in a room like yours, Audyssey will not be making any major adjustments, except perhaps below 200 Hz. I would just run one audyssey sweep at YOUR listening position: let everyone else suffer with an inferior response, after all they didn't pay for the system!