Magnetic levitation feet

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Astronomers and Long Telephoto Lens Users have used Bicycle Inner Tubes modified to be filled with Kiln Dried Sand to absorb Micro Vibrations.
A inner Tube has been Cut to produce a Length of Rubber Tube,
One End is Sealed and the Tube is filled to approx' 75% full.
The Open end is then sealed.
The Sand Filled Tube is then placed on the Telescope or Lens to control resonance that is being detected a blurring of a focus.
I have produced these myself for a friends Manual Focus 800mm Telephoto Lens and they had reported that the View Finder has a improved sharpness.

This has in the past led me to ponder a method that might ?,
improve on the effectiveness of a Inflated Support for a Device.

Using a Inner Tube:
1,  inflating / deflating the inner tube to create a enlarged inner area.
2, remove the Valve from the Inner Tube, and attempt to fill the Inner Tube with Kiln Dried Sand. (A Small Funnel will be useful) 
3, When filled reinstate the removed Valve and inflate the Tube.
4, Experiment with Air Inflation Pressures.

This Method allows for a Combination of Management of resonances,
Air Suspension ( Airborne Vibrations) and
Sand ( Particulate Energy Dissipation )
There are methods already in place both commercially and DIY that address the use of a Suspension/Granular Isolation.

This method I am suggesting is a Simplified Method not requiring too much beyond a already commonly used method of using a Inner Tube.
  
The Inflation of the Inner tube would be potentially at its best
(Vibration/Resonance Control ) ?,
if it was inflated to the pressure to allow the Applied Weight
(Sub Plinth / Device ) , to have a Air Support, with the Kiln Dried Sand being Sandwiched, in contact with the Upper Inner Tube Wall.
How Much compression applied to the Sand can be determined through experiment. 

If a device is with a Uneven Weight Distribution,
Two Smaller Sized Inner Tubes could be used, to allow for the added inflation requirement for the Heavier end of the Sub Plinth and make levelling the Device easier. 

There is Room to experiment with the Air Pressures used,
a cheap Pressure Gauge can be used to record the Pressure that has produced a attenuation that is perceived as offering the desirable audible presentation.       

I believe the feet on the xtension 9 pro-ject turntable work in the same way, two opposing magnets. 

I have these in my system. They work fine. I have a set under my conditioner, one under my server and one under my pre. They don’t hurt nor can I say that they were a night and day difference. My system was very low noise to start with.
keep in mind they come in different heights and weight tolerance. 

The problem with these is that there is resonance control only in the vertical direction. There is virtually no control horizontally. If you have ever tried to push to opposing magnets together by hand you will notice that they push each other away in a very slippery manner. It is hard to keep them opposed. In order to keep them opposed they have to be firmly captured and held in opposition. Springs have some horizontal resonance control but still not as effective as in the vertical direction.
MinusK platforms have almost identical control in both directions which is their claim to fame.