Embarrassingly, the lack of thoroughness has come to an end. I moved wires around
and still had the issue thinking maybe the power cord was rattling against the amp.
While leaned over the sub, I felt it rock a little, very little, but I have a slight uneven
floor, and hardwood at that I was unaware of, so a shim of sorts should fix the issue.
I held the front of the sub down while playing this up to -15db and it was what one would expect
from a Rythmik sub. I stand corrected, it handled the intro just fine.
Now to select a shim material.
I like Sorbothane Islate it bumpers and will probably order a 4 pack from Amazon.
http://www.amazon.com/s/ref=nb_sb_ss_i_4_10?url=search-alias=aps&field-keywords=sorbothane+feet&sprefix=sorbothane,aps,269
It is weight specific and deflects the vibrations off the bulge in the material.
Under or overweighted, and the affects are lessened. This is good stuff.
http://www.sorbothane.com