Hi Darth,
Using special feet under the EP500 as you describe may help a bit, but you still have to contend with the EP500's acoustic deep bass energy that's causing objects (and your floor) to resonate. All objects have a resonance frequency (it's the basis of musical instruments--controlled resonances) and if the bass wavefront is powerful enough, which it is from the EP500, then you will get some sympathetic resonances.
But using special feet under the sub would at least let you prevent some of the mechanical vibration from being transmitted to the floor beneath.
Regards,
