Trace, what you describe isn't at all like the normal bass response of the M80s. Although you said that you looked, I'll suggest that you double check to make sure that the woofers are actually connected. About two years ago a poster reported no highs at all on his M60s. I suggested that he make sure that the straps connecting the terminals were tight. Missing highs found. More complex advice later, if needed.

-----------------------------------

Enjoy the music, not the equipment.