A Copernican View of the Turntable System

Dear Raul: I feel that your posted of 9-11-11 was a direct response to my posts. I would like to make two points in this regard.

First: Being critical of a given approach or "road" as you put it, does not mean that one is against it. I doubt that the purpose of this thread or Audiogon in general is to host forums where people spend there time complementing each other's system. (BTW you have a very impressive system). Being critical challenges these approaches and helps them evolve. While receiving complements is pleasent (I enjoy receiving them as much as anyone) they will only lead to status quo or possibly shinnier and more expensive systems.

Second: you suggest that unless we try a given approach we cannot comment on it. Once again, then why participate on A'gon. I thought the point was to gain from the other participants' experiences and mutually advance. Moreover, I do not have the means to try all that I would like to.

With this said, Raul and the others, please explain the following. With the TT mounted on a suspension system above a mounting surface and the armpod rigidly seated on this same surface how is the distance that must remain fixed between the pivot point of the TT and the tonearm fixed?

The trade off, is between the variations in this distance, most likely in scale of 1/10 to 1 mm vs the variations caused by the micro vibrations from a bearing of a shaft turning at 33 or 45 rpm with a scale in likely 1/1000 to 1/100 of mm. My instinct would lead me to believe that the first problem is far more problematic then the second.

In general, I try to avoid commenting on things that I have no hands-on experience with, or at the very least, have never discussed with another designer who has had hands-on experiences with the topic in question.

This thread is no exception to my policies. I have tried and listened to independent arm-pods on multiple occasions, spanning from the early 1980s to earlier this year.

Any dissent that I may have voiced for independent armpods or other design particulars espoused in this thread, is based on a combination of personal experience (including listening), engineering training, and study and analyses of other turntable manufacturer's design efforts.

Everything that I have learned and experienced about turntable design (particularly regarding DD) suggests that the plinth should have very high moment of inertia but with as few structural or cavity resonances as possible, and as small diaphragmatic area as possible, while the tonearm mount should be non-resonant and completely rigid in relation to the platter so that there is no possibility for relative movement between the LP and tonearm pivot. The reason is that if any relative movement occurs between the LP and tonearm pivot, the cartridge has no way of distinguishing whether the relative motion comes from noise or vibration in the environment, or is part of the LP groove.

This should be accompanied by full isolation from structure-borne noise and vibrations from the environment, and preferably full isolation from air-borne noise and disturbances from the environment.

Some of the posts in this thread very clearly suggest that the poster isn't hearing distortions that should be quite measurable and audible, or that the sound of their system is deemed to be preferable with those distortions present.

cheers, jonathan carr (hugging a pneumatic isolation platform - grin)

BTW, if you place equipment between the speakers, you create an acoustic problem for the speakers, not only a vibration problem for the turntable, CD transport or electronics. IME, if you must place equipment between your speakers, it should present as small of an acoustic profile to the speakers as possible, and should be placed as far away from the speaker's radiating pattern as possible.

Dear T_bone, For someone who is refering to the 'original marketing material' as a 'argument' for his church you should understand how important the right words are. To me
the pedestal also sounds much nicer than a'pod'.I am alas not familiar with the church furnishing but for our church we (should) prefer 'pedestal' above a 'pod'. Ie you and other members of your church are free to pray before a plinth we have, I think, a much more sacral object in our church: the pedestal. Besides our religion is the true and the right one.

Regards,

Pedestals, plinths, and pods oh my! LOL Nandric! You are right. 'Marketing material' perhaps does not have the 'gravity' that one might wish for, though the research behind the concept seemed to be well done.

T-Bone, Nikola,

Pods, Plinths, Pedestals.......? No, I don't think so.

I recommend using a Podium, as the winner always ends up there....

John

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