Springs under turntable

My point was that if you put the box on springs or rubbery mounts, then you defeat

I agree that the speaker has to be fixed. The springs isolate the vibrations from the speaker from exciting the floor - hence the cleaner sound - possibly at the expense of driver fixity. The best sound compromise in this set-up is that the speakers weigh enough to compress the springs such there is little discernible movement AND isolation from the floor is achieved.

The reason why i put 80 pounds of concrete on top of my speakers and it work instead of just using the weight of the speakers only to compress the springs....

Isolation of  2 speakers from one another in the same room is important as much that isolation from other external vibrations...You decrease then mutual resonance amplification...

The springs isolate the vibrations from the speaker from exciting the floor - hence the cleaner sound -

I'd like to see this demonstrated in the laboratory.  Super high-speed cameras and interferometry techniques would do the trick.  If the floor remains static/stable, perhaps it's the speaker enclosure that gets excited.

Guys, I’ve been experimenting with springs in my system for years. I have, maybe, the hardest room type to get great sound out of with it being small and having larger than (I should) speakers in it.

What I’ve done has been a revelation for me. Check out my systems page.

Even within my decoupling platform for my amp/rack, I made an additional platform. The bottom is 3/4" MDF, the top is 3" maple. I recessed the springs into each mating surface at 1/8". The top of the maple platform is recessed to accept 3 halves of Symposium Rollerblock Jrs. The amp mates to the remaining halves. I’m using ceramic ball bearings in the Jrs.

I'm more about experimenting within my room by listening, the old school way.

A good fraction of the energy that causes speaker cabinets to vibrate is coming from the back wave(s) of the drivers in the box, which is an issue separate from holding the drivers stable in position and a reason for the many ported speaker cabinets, which is an attempt to dissipate the sonic energy without exciting the cabinet.  I've always favored Transmission Line woofers, partly for the reason that such designs excite the cabinet very little, resulting in a very clean output.  The only woofers or subwoofers that I have successfully mated with my ESL speakers have been TL types. The cabinets of my home-made TL woofers that I use with Beveridge 2SW speakers are constructed of 1.25" thick HDF and weigh about 100 lbs each.  They don't move.  But given the fact they are TLs to begin with, they aren't very excitable, either.  Maybe this helps explain why I say that there are two separate issues with vibration and resonance.