Upgrade from TW Acustic Raven AC-3 to what?

Managing the vibration introduced by the tracking process is a different matter. This is not disputed in any way by me. However - the isolation from OUTSIDE vibration traveling into the TT - is essential, a true conditio sine qua non. The inherent vibrations have to be eliminated inside the system (here: TT) - the external vibrations have to be kept away from the system (again: TT...).
An ideal solution/scenery: different room to eliminate sound pressure effects PLUS isolation from building resonance by means of a vibration isolating platform tuned for below 2Hz resonance frequency - 0.5 Hz if possible.
Regarding the isolation from outside vibration TT's (at least the ones worth mentioning and claiming themselves to strive for the state of the art) do indeed have the very same needs as an electron microscope.
Avoiding having the very tiniest details smeared by low frequency outside vibration moving into the TT system.
Anyone not accustomed to this, I strongly recommend giving their beloved TT a listen after setting in on a Vibraplane or Minus-K with enough load close to the maximum allowance.
The following listening will answer all questions in a matter of 20 seconds.
I know it - I have watched the faces of various audiophiles often enough in those first seconds.
After that all critics turned to true believers in the simple laws of mechanic.
But - its kind of costly and won't work with some of the fancier "high-end" rack due to lack of guts (here: stability).
It doesn't look to good either.
A well loaded Vibraplane moves into the game very much like a solid full linebacker with 240 lbs+.
But after all - this is a game for real men.
And here once again the boys are separated from the men - as the later do what has to be done and not just talk.
Enjoy the journey,
D.

Isolating the turntable system from external and airborne vibrations is certainly essential. That creates one point of vibration attenuation and frequency reassignment from external influences.
A lot of the above discussions seem to bear on the issue of the various interfaces of the vibration detection system, itself and how they "drain" into this interface between the turntable system and the outside "world".
For instance, a theoretically perfect rotating platter with a perfect gravitational field on a perfectly frictionless air or magnetic bearing creates another point of isolation within the turntable system itself. Also, the more frictionless the bearing, the cartridge modulations and imperfections of the vinyl will create centripetal and centrifugal de-stabilization effects over time which can only be reflected back into the vinyl/cartridge system from the platter to the cartridge. I imagine this is why the Caliburn system unloads the mass but preserves a mechanical interface, to stabilize this interface and create a point of vibration drainage apart from the cartridge interface, itself.
Also, a linear air bearing tone arm, also theoretically frictionless, creates another point of isolation from the internal interfaces of the turntable system. Although this may minimize tracing distortion, it creates two different effective masses and another isolated vibration interface. Unless the damping from this system is perfect, the cartridge sees reflected vibrations from the tone arm system itself without an external source of vibration drainage. Also, if the friction is theoretically zero in some dimensions, the cartridge is free to wag the tone arm without inhibition and is not restrained around the groove modulation. So this system is not restrained or drained as with a mechanical inerface.
If you have an air bearing platter AND an air bearing tonearm, you have two theoretically frictionless points of isolation mediated by the cartridge interface. This seems like you have one tail (the cartridge) wagging two dogs (platter and tonearm) against two points of isolation without drainage, relying on perfect damping from the two points of isolation. I don't really see how this is ideal even in theory.
Also, on SME website, they cite that material density and stiffness are at least as important as sheer mass. The SME tables create a "mass effect" by using stiff, high density horizontal plates and turntable platter rather than sheer mass.

This discussion is going in a direction that isolation (passive or active) is the solution for everything. I am sorry to say, it is not. It is a step up in Performance but an average Turntable placed on a isolation device is still an average turntable. It only sounds a little bit better than the same without it. A cow will be no horse.

Syntax, it might me a fruitful approach to test the halcyonics duo or/and the halcyonics sandwich, also against the Vibraplane. As they say they produce custome made units at the moment you get a sandwich unit only in 800mm x 800mm which is somehow an oversize for most audiophiles.

As you might agree we both are not keeping cows in our barn or do we?