The Rubicons are now sitting 4cms higher on these slightly wobbly Canadian pucks which adhere to granite slabs. My listening room has a carpeted suspended floor and the extra deep bass of the Rubicons over the Opticons was causing vibration in the structure and a suspicion of bass overhang. Not only is the bass cleaner and better defined, all discernable vibration has been mitigated. An unexpected bonus is improved image, vocals and soundstage. Not cheap, but not as eyewateringly expensive as Townshend seismic podiums. I am surprised that even barely detectable bass boom/overhang is so detremental to SQ. Final, final post from me and happy listening to all.