You have a couple of things going on. First, your room is way too big for those speakers and especially the subwoofer. Audyssey might be trying to compensate for this, resulting in poor sound. If you haven't, turn off the Audyssey EQ (keep the levels and delays) and try that out. If it sounds ok, then the Audyssey processing is your problem.
The second issue is the placement of your speakers. Having your front speakers so close essentially makes them act like a mono source. This will cause comb filtering (makes the FR look like a comb with a set of peaks and valleys) when two or more speakers are active. Their proximity will also make any spatial effects (pans, person entering a room, etc.) difficult to discern, contributing to a boring sound.
Give these things a try and let us know the results. I think this may be an issue of Audyssey not playing nice, but it could be placement-related too. What levels does Audyssey set your speakers at? How are your speakers supported (stands, wall-mounted, etc) and how far from the walls and floor are they? As mentioned above, you might also consider trying your friend's Yammy. That, however, will only tell you if your Onkyo is broken (receivers sound the same with processing disabled).