A Copernican View of the Turntable System

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.

-----------------------------------------------------------

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

Dear Jonathan, I guess I am in good company. When you wrote, "...a more elegant, and technically correct solution is to mount the tonearm pivot and platter / spindle onto a single rigid structure that allows everything to move together at the same rate and same distance (and phase), then isolate the complete system from the environment by means of an isolation platform (not footers)", you pretty much echoed my position on the subject. Thanks very much for taking your valuable time to respond.

One thing though.... chocolate IS better than tomato, except at this time of year when our tomato plants are producing great tomatoes faster than we can eat them, thanks to my wife.

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.

It is hard to argue with this statement and, like Lew’s ‘Galleons on a stormy sea’ analogy, it would seem to preclude further development of the ‘isolated armpod’?

But ‘theory’ and ‘practice’, when it comes to audio, are often uncommon bed partners?
For instance, there are good theories for the superiority of belt-drive over direct drive turntables…..and vice-versa….yet both can deliver fine practical results.
There were (supposedly) good theories behind the superiority of digital over analogue as the ‘source’ material in audio reproduction yet in practice (according to vinyl advocates), those theories have still not been realized?
There are good theories for the superiority of Moving Coil cartridges over Moving Magnet cartridges yet in practice, (according to some advocates), those theories do not always apply?

The ‘theory’ regarding air-borne sound transmission affecting the analogue playing system is also ‘undeniable’?
All the frequencies of the audio spectrum from 20Hz to 20KHz (as well as sub-sonic and ultra-sonic frequencies), bombarding the delicate parts of the turntable/arm/cartridge system must induce vibrations within those parts which will be amplified and projected through the speakers?
If this theory is correct, then scientifically it must follow that the higher the volume, the greater the induced vibrations.
In practice this must mean, that as we turn up the volume, the sound quality decreases?

I have heard the reverse to be true. Up to the limits of amplifier distortion, speaker ability, room configuration and turntable quality, generally the higher the volume level, the better the sound quality.
I have even heard turntables which are located in separate rooms to the speakers and to my ears, the sound quality is not improved?

So ‘theories’ are great if one needs a starting point from which to commence a design, however in audio, there seem to be many other overriding factors which render many known theories of physics to play, if not negligible, then very minor roles?

Audio is not a religion and I attempt to convert no-one here. If one hears a benefit, let on-one corrupt the reality with ‘unproven’ theory.

Halcro,
A couple of thoughts...

I think we will all agree that just because the 'theory' is not borne out in 'results" does not mean the theory is wrong. In many cases, the 'not-as-good-in-theory' concept is far better implemented than the theoretically-correct. My Micro Seiki belt drive sounds far better than my Technics SL1200 but my Exclusive P3 sounds better than a Rega P3.

I too am not 'religious' about audio. Personally, I think several of the arm pods developed here are probably capable of permitting excellent sound (arm/cart/implementation permitting). Reading this thread has given me some ideas. And it makes me want to have a crack at something similar too. A 10-20kg arm pod is a prodigious weight, and in practice, that kind of weight will couple the pod and therefore the arm bearing to the surface below the arm pod. Pods are not necessarily like galleons on a stormy sea in practice. That said, if I implement pods, I will seek to couple the pod and the motor to a single rigid surface, and then isolate that rigid substructure. Doing so will get me somewhat close to Jonathan's concept.

Many of us, myself included, are firmly in the camp of improving our systems any way we can. That necessarily requires experimentation. And in many cases experimentation is assisted by forming a hypothesis, which for practical purposes, until proven, is really all a theory is. In many cases, there are practical obstacles to going down the road of perfect theory. Your point about MCs vs MMs is an easy case in point. The theory that MCs are intrinsically better than MMs requires that the pre-pre stage (head amp or step up transformer) be capable of not limiting the effective performance of the MC. I think in practice that aspect limits the performance many get from their LOMCs.

As to your points on air-borne sound transmission and its effect on turntables... All I can say is that if you have never noticed it, you have been extremely lucky, or extremely good, in your room set-up. I have not been either and have heard the effects. Even when my P3 is well away from my speakers, listening with top up or top down is different. If you have an ADC, testing the effects of sound transmission on analog playback, and of the effect of greater volume, is relatively easy.

In any case, I applaud your efforts at experimentation thus far. It really is all about living with and enjoying the result.

Ct0517,

It would seem that our experiences defy the theory. As a certain phiilosopher once said, in that case, the theory needs revision/refinement.

An old Chinese saying: black cat or white cat, the right cat catches the mouse!