The 'punch' is around 50-70hz give or take a few hz. I run my M80 at 40hz just to get more punch/feel from the system.

Do you stil have the SVS subs running as well? You could also just be used to the more punchy bass the SVS subs pump out compared to the smoother sounds an Axiom sub produces.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70