Sandbox-style isolation

Dave, the sand should move in both the vertical and horizontal plane as well,

It still seems to me a mass loaded design should sit on the most stable platform you can provide, seems some non-sympathetic vibrations would be induced by more compliant platforms. Therefore, vibrations of different parts of the tt are moving asynchronous to each other, inducing confusing movement to the entire mechanism. Sitting on segmented plinths should only increase this confused movement.

I should add, every move I've made towards a less compliant plinth and more massive platform has resulted in increased sonics, specifically, much more coherence, solidity, slam and bass articulation. Any compliance sounds smeared and soft.

I plan on making a 10" sandbox this summer to gain yet more stability and mass. I'm also trying to find some wider aluminum L brackets in order to get more vibrational drainage. I always think about the massive plinths and platforms of the Brinkman and Continuum tts, I'm sure a lot of their superior sonics come from this mass and the stability it imparts.

I have yet to beat my DIY sandbox with my Scoutmaster. Many are using sandbox isolation with their VPI's, most seem very satisfied. Tried various suspension type isolation schemes, didn't like those at all, I suspect mass loaded designs like vibration drainage. Sand and aluminum together do a first rate job, check out the Galibier tt website (DIY sandbox design, or could use this with commercial sandbox), Thom had my solution. I think you would have to spend a lot more to get much better, something like the Grand Prix line.

I can tell you from my own experience the single aluminum plate using the vibration sinks, per Thom's instructions, is superior to the segmented top plates I've tried. More refinement, resolution, more slam, solidity, greater dynamics. Now, I've thought about segmenting the aluminum plate, Thom's argument makes sense, I will not segment.