Vibration isolation or absorption?

From Clearthinker, above, it appears that I may have stumbled onto something correct, for a change. My audio space is on a slab, with carpeting over it. My speaker stands are connected to the floor via spikes, without any saucers. My speakers sit on small nylon isolation feet, mostly to protect the finish, but it appears they may help decouple the speakers, a bit. I find that this spike/squishie system works great until at higher volume my room acoustics screws everything up.

+1 Clearthinker

Rabbit hole

I think you can only hear a noticeable difference with isolation or not on a suspended floor. Concrete floors are much better 

Whenever I see speakers on stands with spikes - and I have no experience with spikes - I wonder if they’re vibrating some of their energy into the stand itself, and thus losing some of their refinement.

A pair of Ohm Walsh II’s - and Magnepan too - sound bass-heavy and muddy in the low end, and vibrate the floor - the Walsh far more than the Magnepan.

Up on Sorbothane hemispheres, no vibration, bass issues gone, and the soundscape becomes properly tight and they can handle much more base.

A pair of Infinity Kappa 6 don’t sound bad on their stands, but they sound noticeably finer when isolated from the stands.