Best rack for non-suspension turntable?

Audiavreseller, I don't think the Minus K is a active isolator as it doesn't use electricity. I think it too is just springs done in an innovative manner. The Audiav clearly is just a rack. The only active isolator is the Halcyonics which I will attest to as exceptional.

Every material has a set of resonant frequencies (mode spectrum). I believe you may be referring to the boundary conditions that apply to the problem and this is why I qualified my comment with the phrase "All other things being equal, . . . ." The example of a partially buried telephone pole shows how boundary conditions affect resonance - one end of the pole is clamped, which shortens the effective length of the pole and raises the resonant frequency.

Layers of adhesive or semi-adhesive polymers like Sorbothane also have resonant behavior; the natural frequency depends on the size and shape of the layer. The product web site has data and a nice downloadable calculator to compute resonant frequencies for various applications. On looking into this, I was interested to learn that it's pretty difficult to get the material's resonant frequency much below 5 Hz in any real-world application, especially for thin layers covering large areas.

I'd also like to point out that the Minus-k products contain no servos; they are completely passive. The principle behind these products is to use a coupled spring-flexure system in which some of the springs are near their buckling points. This can create a negative-stiffness situation, hence "minus-k."

My misunderstanding with the Minus K... there are so many different racks out there; I may have been confused. I think someone had mentioned them being active as many of the active platforms that we have tested and even on my data sheet has been errantly marked active. I could have sworn the Minus K plugged in, leveled and even displayed when vibration was present. I think I like the Minus K much more since they are not an active servo system... what a nice intro they have with the wine glasses from a passive device! It is very hard to control very low resonant frequencies and will be the FIRST to say that ANY rack cannot dampen 100% of the spectrum especially at higher than miniscule velocities.

Audiavreseller, it is the Halcyonics that is active and far superior to the Minus K. I own two and wish I could afford more.

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Tbg,
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Have you heard a Minus K in your system and done a direct comparison between the Minus K and the Halcyonics ?
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If not in your system, have you heard both devices compared in the same system at the same time under the same piece of equipment ?
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Rgds,
Larry
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