I've had my new system for about 2 weeks now and am really having a problem with the bass 'sound' for music listening. System consists of: Onkyo TS-DX696 reciever Sony DVP-NC600 DVD player (relatively low end - $230) HTD Level III 5.1 speaker system (not towers) This is in a large room (20x25) with vaulted ceiling slanting from 8 to 16 feet high in the 25' direction. I've been listening to music in Stereo mode, from seating location near middle of room. I have all speakers set to small (claimed response for the mains & surrounds is 43-20k, 30-250 for the 12" sub) and the sub XO set to its highest setting. My complaint is the bass just sounds way too 'much'. I guess that boomy or muddy would describe it. Maybe I've been bass-deprived until now and this is how things should sound, but I just don't like it much. For what its worth, my musical tastes run to rock and blues, and I do like it LOUD. I have the Avia DVD and have used it to the best of my ability in conjunction with a RS digital SPL meter to calibrate the levels. I've been reading this and other HT forums like crazy and I'm starting to understand some of the discussion. With respect to Avia,I've performed the subwoofer phase testsr repeatedly, and can hear no difference resulting from changing the sub phase switch from 0 to 180. I've experimented somewhat with moving the sub around (corner, against wall between front speakers, in middle of room under glass end table) and affect is similar in all locations. I read a thread with commentary by a guy named Brian Florian and if his comments are relevant, maybe this HTD sub is just not up to par. Any advise would be most appreciated !!