You're sitting too far away given the 5' speaker separation. As an experiment, situate yourself 5' away from the speakers to see if there is a difference. Also, 5' of separation may not be enough to achieve a stereo effect.
Midrange is a perfectly acceptable term for a driver that spans anywhere from 100Hz to 3KHz. I find it surprising however that Axiom calls its woofers sub-woofers. A sub-woofer handles frequencies below 30Hz (and this is the M80's half power point). It would be interesting to know how these designations were arrived at historically.
