Footers under my speakers double the perceived value of my speakers!

I live in earthquake country.  Putting ultra-minis under 200 lb speakers does not seem wise for my speakers.  My 185 lb speakers rest on four widely spaces metal cones into a 12" thick 3000 lb PSI steel reinforced slab.  Vibration is not a concern from below the speakers.  I intend to purchase speakers weighing 600 lbs each.  No way am I going to mess with the speaker designers footers.  The thought of putting something like tiny footers in unfathomable in earthquake country.   My other 135 lb speakers also have metal cones but on a 4" thick maple block on a carpeted rug on a standard slab.  It has a downward firing woofer (among 3 total) which does not like hard surfaces (metal, granite, etc). that I tried.  Maple sounded better than carpet by a tad.  

Sure, I put footers under some flat bottomed older two way speakers for my video system that weigh under 40 lbs each and raised them off the floor (which is standard 3 1/2" concrete slab) and that tightened up the soundstage/imaging/bass.  

I use several types of Stillpoints most of my equipment. My new DAC does not sound good (hard or unfocused) with Stillpoints, cones or vibrapod type footers. It was designed with vibration in mind. My amps, 2 pre-amps/phono preamp, analog speed controller and digital transport were not as well (or at all) vibration designed and need Stillpoints. The shelving is 1 1/4" HDF on solid rubber isolation pods on steel ball bearing/sand filled welded steel stands (made for audio) on spikes into the above 12" concrete. I experimented with at least 10 different companies footers and more types of products and stuck with Stillpoints. The Townsend sink is 100% necessary for my VPI TNT VI which has bad isolation/vibration lack of control.