Tonearm mount on the plinth or on Pillar ?

The trouble is that the instabilities and so forth in the Earth’s crust and other sources of low frequency vibration actually force the entire building structure, house, apartment building, converted ICBM missle silo, whatever to move like a carpet being shaken such that everything inside the building is also forced to move and all attempts to control this very low frequency vibration with damping methods won’t accomplish squadoosh. This is not to say that damping doesn’t have it’s place. I’m actually a big fan of contrained layer damping in applications such as CD transports, output transformers, the top plate of iso platforms and capacitors, among other things. Even very rigid structures and stiff materials have their place in vibration isolation inasmuch as they can help control bending forces produced by Earth's crust motion.

You said that was correct....
You then contradict yourself by writing:-

The result is it is quite impervious to the volume level in the room; even at 110 db the sound is still very relaxed.

The two statements are logically incompatible.
No amount of plinth dampening will avoid the effects of air-borne sound waves on the vinyl, cartridge, stylus and tonearm.
The fact that you and many others can listen to vinyl played back at excessive volumes demonstrates conclusively that air-borne sound waves have no effects on the turntable system.

Actually I'm not contradicting myself at all- merely point out that the design is successful. I assume from your post here that you did not actually read the post from which you quoted or such would have been rather obvious.

I've been digging through this to the point of multiple circular thinking all leading to nowhere. My comprehension, while not fully through, does lead me to question many of the tenants expressed here, if only due to being invested in a TT/plinth?/tonearm which violates almost every principle presented here for superior SQ. 
Trans-Fi Terminator tonearms , linear tracker with air bearing. Salvation TT with magnetic bearing, floating for all practical purposes. Resomat platter pad which further isolated the LP from the platter. nothing is connected with respect to vibrations being transmitted concurrently during playback. Sounds great. 
I did follow Terry9 and place a little damping material  on the arm wand to some good effect. 
Maybe it's my tin ears but it sounds really great to me.

Dear Halcro, You wrote, "The fact that you and many others can listen to vinyl played back at excessive volumes demonstrates conclusively that air-borne sound waves have no effects on the turntable system."  But that is an incorrect assumption based on all my past experience.  I have been present many times, in many different listening venues, when acoustic feedback causing distortion was sound-pressure-dependent.  Backing off the volume control could reduce the effect and eventually eliminate it entirely, in these instances. Perhaps this is not a problem in your house, but it is a real phenomenon in some others. In the case that Atma-sphere (Ralph) describes, perhaps conditions were such that there was no appreciable acoustic feedback, even at 100+ db. It's possible.  Careful set-up and room damping can indeed eliminate or remove the problem, but that does not mean it does not exist.

Dentdog, More to the point, is your Terminator tonearm mounted on your Salvation turntable or is it on an outboard arm pod, separate from the turntable?  The Resomat is indeed a contrarian design in that it specifically decouples the LP from the platter, whereas most platter mats make an attempt at coupling to facilitate the dissipation of spurious energy delivered into the vinyl by the passage of the stylus in the groove.  Many do say the Resomat works great, however.  Which should make us re-examine the theory of the platter mat.