European Vibraplane?

The Vibraplane was a Newport Corp. microscope stand modified to provide lateral isolation in addition to vertical, not sure about the rotational directions, possibly rocking and rolling isolation. Since the Earth Crust motionproduces a lot of energy in the 0-10 Hz range, every Hz you can reduce the resonant frequency is important. Below 1 Hz would be outstanding. The number of directions of isolation is also pertinent. As I recall the Minus K has a resonant frequency of around 0.5. Now we're talking!

Townshend Seismic Platform looks interesting, from UK.

http://www.townshendaudio.com/hi-fi-home-cinema-equipment-vibration-isolation-platform/

It's an interesting question which iso platform is The Best since a lot of the "art" of isolation involves how the platform is supported, how the component is supported and, like you say, how bad the situation is to begin with. We do know that Earth crust motion, in and of itself, is sufficient to cause problems. Halcyonics, a Swiss German iso table, is interesting and there's always Newport Corp. and TMC. Myself, I like hardened steel springs and heavy masses.

Syntax wrote,

"I also listened to Minus-K with the same turntable...good luck with that units. It starts moving even when you move the Tonearm to the first track. Even when someone would pay me for it, I would refuse to use it. They are ok for units with centered weight, but that's it."

The best isolation occurs when the motion is obtained with the greatest ease. It's a blessing and a curse. ;-) However, this might not be advantageous for turntables and even CD players that produce rotational forces. As I recall the Minus K negative stiffness machine used to be the Newport Corp Sub-Hertz Platform of yore and was modified for the audio market. Ooops, there's that name Newport again. I was under the impression that the rotational capability around the vertical axis of the Minus K had been disengaged but I might be mistaken. I also recall that the (Newport) Sub-Hertz Platform would go into its rolling swaying motion of 1/2 Hertz when a penny was placed on the top surface.

Mechanical springs have some interesting advantages over air bladder and air spring systems. It is much easier to maintain mechanical spring iso systems since there are no porous rubber bladders, no air fittings that can leak and no air pumps to buy. Mechanical spring systems are inherently self leveling and since hardened steel springs don't change their spring rate over time like porous fabric of the air springs/bladders they remain level.

Mechanical spring systems are not over-damped, whereas air bladder and air spring systems, due to the nature of many stiff rubber bladders/springs, can be over damped. Mechanical spring systems are much easier to tailor to load requirements - the only thing the user needs to decide is what type of material he wishes to use for the heavy mass, if any. Smaller size mechanical springs do not require pre-loading with heavy mass if the component weighs enough - another advantage. Smaller springs, by virtue of their low profile, are very stiff laterally so they can support loads with relatively high center of gravity such as turntables with high-mounted heavy platters.

Finally, mechanical spring-based systems are inherently inexpensive since the springs themselves are inexpensive and heavy masses can comprise almost any stiff, massive material like granite, flagstone, bluestone, marble, even stacks of ceramic or marble tiles, many if which are inexpensive and easily obtained. Plus no air pump is required, and no air fittings. Resonant frequencies of simple mechanical spring based iso systems can be obtained on the order of 2-3 Hz without much difficulty.

Peterayer, it's more of a DIY project, I am pretty sure there are no commercially available units like the ones I have in mind. I designed the first Sub-Hertz Platform for the audio market, the Nimbus Unipivot, a 6 degree of freedom, single airspring design, about 15 years ago. I developed a mechanical spring based platform, the Promethean, about 10 years ago, the primary advantage of which was that it was modular and could support almost any load, unlike Nimbus...and it was a 2 Hz stand. Some of my Promethean customers had really big turntables like Raven, VPI and Verdier, also amps like JC-1 and the big 200 lb Classe amp. My current DIY project is based on small hardened steel springs and heavy mass. Because the springs are only one inch high compressed they can be placed directly under the component in many cases.