A Copernican View of the Turntable System

Thuchan,
This is, as Dgob points out, only theory. However, following that theory, one would say that having armpod and turntable on different isolation platforms would be sub-optimal. One could see this by having the table be absolutely, perfectly stable and putting the arm pod on top of a sponge-y material - the arm-mount/arm bearing is isolated/coupled to a different extent than the table bearing. Any movement anywhere (the ones your isolation platform is supposed to counteract) will lead to distortion because of the mismatch in response of the bearing surfaces. Putting both on separate isolation platforms does not necessarily improve things as trying to match the resonant frequencies of the two isolation platforms in both frequency AND phase is almost impossible (primarily due to differences in platform loading leading to both different frequency and different reaction time to a given impulse). Or so the theory goes...

Thuchan,T_bone is referring to the "cantilever effect". A separate armboard/armpod should be linked to the plinth by means which are as rigid and as stiff as the material of the plinth itself.
Otherwise you would create an "elastic joint" similar to a cantilever.
In the very same sense a separate/free standing arm pod in it's relation to the plinth/turntable is "connected" to the plinth. With inevitable effects on energy transfer and resonance behavior of the "closed circuit" mechanical system (here: stylus/cantilever - tonearm - arm pod - common ground - plinth - bearing - platter - record - stylus/cantilever).
That's what Jcarr meant when he was referring to the "grounding principles in amplifiers".
Cheers,
D.

Dear Thuchan, It is impossible for me to resist the temptation. You can probable also use the shild surrounding to protect yourself from radiation in case of an nuclear war.

'Peace',

Dear T-Bone, Dear Dertonearm. Oh yes theory is a wonderful thing but are there any experiment documentations available which support the "cantilever-theory" as well as the "isolation theory (of different platforms)".

Funnily I made the experience when I put the motor drive and the three legs (feet) of the Continuum on extra platforms the sound is quiter and dynamically better. I would never return to a non isolation concept.

Nandric is right he knows how to handle the issue seriously ... :-)

best & fun only

Hello Jonathan Carr – I want to say that I find your posts on this public forum always very informative and helpful no matter what the thread topic. As a manufacturer you are quick to point out any biases and I appreciate that you usually recommend to us to use our own ears for the final call.

THEORY PART

Jonathan Carr stated.

A) Mounting the tonearm on a separate pod allows relative movement to occur between the tonearm pivot and the platter / spindle, and this will interfere with the "accuracy of measurements".

This sounds very technical and something that would come out of a white paper. It is a statement that would give designers/manufacturers a direction to take in the manufacture of TT’s. It also sounds very logical to me at the macro level. I have no problem with it.

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Now here is another broad statement that I have read about Armpods on the internet. Original Author unknown.

B) Isolated Armpods break the rumble feedback “loop” as it happens through the plinth as it contacts the arm at both ends - through the arm pillar and cartridge via the platter.

This also sounds very technical to me again and "also" something that I think could come out of a white paper. It is also a statement that would give designers / manufacturers a direction to take with the manufacture of their TT’s and also their Armpods as a package together or separately. It also sounds very logical to me at the macro level. I have no problem with it.

FACTUAL

This vinyl hobby is a very “crude hobby” no matter how “pretty” we make the components look and how technical we make our language about it. Such expensive mechanical or structural components whose job together is to send “vibrations” along picked up from a crude piece of vinyl plastic, of which NO TWO ARE ALIKE.

I have watched how these lps are made. All of vinyl’s inaccuracies 1) warps, 2) not centered spindles, 3) varying thicknesses, 4) varying grooves 5) fill in others …
This has led to a plethora of devices out there to help mitigate these inaccuracies. Look at all the devices trying to get the best alignment out of just two specific points on this piece of vinyl. The remaining points on the lp become even less accurate. All of this makes words such as "accuracy of measurements" start sounding to me on this public chat forum, like square pegs being tried to fit into round holes? No matter how accurate the process is in building the actual TT player itself and its components. You are still dealing with that piece of vinyl as your source.

SETTING THE RECORD (no pun intended)

I am in no Pro camp here – never have been. I am only Pro sound for me in my room/s. I am a user here – I am not a manufacturer, designer, dealer, distributor or anyone that benefits in any way from having someone’s equipment in my room like some others here. My latest TT has a 100 pound plinth. I have multiple TT’s that I own and of the three in my modest sound room, one uses Armpods.

For the last 30 years my occupation has been in the field of RISK Management Planning and Mitigation. I get dropped into companies and my team needs to come up with solutions to their specific problems. This work involves macro and micro analysis, design and solutions.

Now if I was being asked my professional work opinion here based on all this theory and my real listening tests, my professional response back would be that both of the above statements (A) and (B), make logical sense at the macro level and the ultimate micro TT detailed solution must take in and incorporate the advantages of both.

PHILOSOPHY

I am a big believer in the BIG ROCK theory. Not just for this hobby, but for my family, and my occupation. I consider myself a music lover first then an average audiophile. I have only myself to please. I have been told I am a very stubborn person.

SUBJECTIVE PART

My opinion as a user and after real testing and real experimenting in my own room are that even though A and B are I believe, both logical statements. For what I am actually hearing (B) represents a bigger rock than (A). I believe I am hearing the advantages of (B) and they overcome or cover up any problems with (A) - or if not - someone here should stop with the theory and tell me what I should be listening for to indicate (A) problems.

In the meantime I have not completed all my planned testing, but so far I feel the isolation this Pod provides helps to move me closer to my nirvana. I am content and having a lot of fun listening to music, not worried if my 16.6 lb Brass Pod or Platter and Motor are moving on me.

Cheers Chris