Springs under turntable

mambacfa, in the case of industrial machinery you are trying to isolate everything else from the vibrating machine. Listening to the machine vibrate is not the objective. I think that is quite different from a device that is intentionally either producing or reading vibration that has to be transferred in an accurate way. The reader has to be protected from all other vibration in the environment and the producer has to be locked in space so that it does not produce any unwanted vibration.

No Flatblackround. I think he is doing cocaine. That produces zero stiffness:)

First, I apologize to Millercarbon for my snotty tone in the context of my reply to his post about springs and such. I find myself in an irritable state of mind probably due to months of isolation and jitters related to the upcoming election. Only my wife can stand to be around me lately.
Second, I must say for the second time that "we" are confusing "vibration" with the pure problem of controlling the motion of a speaker cone. The box has to hold the body of the speaker stable so that the energy generated by the amplifier to move the cone is converted only into motion of the cone. This is never perfectly achieved, of course. My point was that if you put the box on springs or rubbery mounts, then you defeat the effort of the designer to hold the frame or body of the woofer stably in space, while the cone delivers its energy to the air. Instead, the whole assembly is now able to use up amplifier energy in motion that is opposite to the desired application of the force applied to it."Vibration" is certainly a resulting issue associated with the effort to maintain rigidity of the mount, but controlling or dissipating vibrational energy or resonance is after the fact. Do we know of any commercially available speakers that are supplied from the factory with springy or rubbery feet? I cannot think of one.

Picture a naked woofer hanging from a string or springs in mid-air and trying to reproduce a bass tone. Can you see that it would bounce back and forth in directions opposite to the excursions of the cone?

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.