A Copernican View of the Turntable System

Dear Lewm, as a direct response to your post 01-18-11, I think that the most important energy in the turntable system is in fact emitted by the tracking process itself. The rotating platter is not the problem (in fact, it is a rather self-stabilizing force increasingly resting with increased inertia).
The tracking process (the more so with low compliance and direct-coupling cartridges - Ikeda, SPU, DECCA) does create a source of energy (vibration) traveling into the record, into the platter, into the tonearm and creating resonances, reflections and ( all mass and material depending...) standing waves in the material.
Those are the demons I want to illustrate.
That energy is traveling and should find a way to leave the system fast as possible with leaving as little resonances and reflections as possible along the way.
A poor plinth will react to that energy with resonances and reflections and such cloud, alter and spoil the sonic performance.
VTF is part of the problem ( but only in relation to the corresponding compliance ). Skating is not.
High-compliance MMs will be much less of a problem.
A reason why cartridges like FR-7, SPU, IKeda, DECCA/London do perform to their very best on high mass platter tt's with massive frames, very rigid tonearms and platter weight above 30 lbs. To me it's a game of energy and masses - and the material mix.
Cheers,
D.

Dear Halcro, Lewm, Raul, et al - I assume that on a whole we all do in fact agree on the topic of "bad plinth" tt vs "naked" tt ( in the sense of the absence of a poor designed and resonate plinth which doesn't add any good to the performance, but is just a source of sonic distraction ).
If we include tt-designs like Micro Seiki 5000/8000, Raven AC/BN, PV and the like into the "naked" camp, then I absolutely agree, that a "naked" tt has considerable advantages vs "classic plinth" - types with wooden frame around a spring-"isolated" sub-chassis.
Then we have main-frame types like Thuchan's Continuum Criterion, which falls somewhere in between ......
But here it is done with huge input (money- and manpower...) and some smart ideas.
Ultimately I think it always come down to this.
IMHO ( ... ;-) ...) the solution might be found in an extremely rigid and dead silent "mainframe" holding the armpod/base and the bearing. That frame should be pretty massive, compound and compact so to display minimal tendency to resonate.
Cheers,
D.

Dear Halcro, In response to your consternation about my statement, I guess I should not have used the word "introduced". Better to say that with no plinth, some resonances are or might be left undamped that might more often than not be pleasing, to a given listener. In other words, an error of omission, not commission. Nothing wrong with that, it's just a thought.

Dertonearm, As I told you privately, I take your point(s). I cannot think of that massive piece of metal that comprises the base of each of the big M-S turntables as an example of "no plinth". To me, that's a bloody good plinth. And those are belt-drives. Their more feeble efforts at direct-drive, the DDX- and DQX1000, which do have essentially no plinth are not so highly regarded. (Never heard either.)

Pardon my arriving late in this discussion.

If I can weigh in on something for a moment? I think Dertonarm and I are in agreement here: the coupling between the base of the arm and the platter of the 'table must be exact and profound. To that end, there can be no play anywhere, with the plinth being both rigid and non-resonant.

If the arm is mounted on a separate 'island', it will be impossible to reproduce the LP exactly, as any differences between the platter surface and the arm base, for example microscopic vibration or resonance, will be interpreted as coloration by the reproducer.

The system of platter surface, bearing, plinth coupling to the arm, the arm and finally the cartridge can be likened to the steering and suspension of a fine motorbike or automobile. Any slop or flex in such results in handling problems!

So quite obviously a plinth that has resonance and/or is not perfectly rigid, an arm with slop in the bearings, an arm without a rigid, resonance-free arm tube, a platter with resonance and a platter bearing with slop will all contribute to coloration in the playback.

Right on, Ralph!