Tracking error distortion audibility

Raul and Dertonarm,
Does either of you have an opinion on whether or not the advantages of lower theoretical distortion of a 12" arm outweigh the disadvantages of greater moving mass and potential for slight stylus misalignment being amplified more in a longer arm?

I'm curious about the differences between the 9" SME V and the new 12" SME V-12. This topic is discussed by Michael Fremer in the latest Stereophile review of the SME 20/12 and I'd like to read your opinions. Thanks. Peter

Dear Peter,
we have to mate either tonearm with a cartridge with perfectly suitable compliance, - if done so, there will be no trade off in moving mass vs. effective length.
Given an ideal match with the compliance of the cartridge, we can assume almost identical conditions in terms of resonance frequency.
So the geometrical advantages of the 12"-tonearm will prevail.
The sonic advantages will be especially noteable on well recorded opera with comperatively large soundstage.
The sonic presentation of the soundstage will be much more stable and the positions of the various singers and their movements on stage will be more precise.
So - as I see it - there is no trade off between moving mass and geometrical advantage.
I do not want to call again and alone the example of the FR-tonearms (the FR-66 will always beat the FR-64s with any given FR-7 system), so lets go to Ortofon instead:

- do mount a SPU in a 9" Ortofon and in a 12" Ortofon tonearm. Both do have effective moving mass together with the SPU which will result in resonance frequency very close to each other (but it will be lower in the 12" Ortofon). Given exact mount and alignment to the same geometry (Baerwald, Loefgren, Bauer, Stevenson - no matter which, as long as its the same for both), the 12" will prevail in terms of size of soundstage presented, ease of tone and naturalness.
All these features are related to lesser derivation from the zero-error-curve - because the 12" tonearm does come closer to the theoretical ideal tangential.

Dear Peter: Your question IMHO has mre than one answer because there are mre than one factor involve.

If we take from the geometry point of view the 12" tonearm always will has advantage ( in theory ) over any other shorter tonearm. But unfortunately things are not so easy.

Looking to LOMC today cartridges the first " trouble " that we have is that the same cartridge, say a Titan i, will have a different resonance frequency with the SME 9" than with its " big brother ", this fact alone preclude a fair comparison ( and I'm not saying that the Titan is the best match for the tonearm, I take it only like an example. ) because that difference in the resonance frequency has its own " sound signature ".

Other subject that Dertonarm already point out: +++ the further away the cartridge is, the higher its influence on the mechanic resonance behaviour of the tonearm. +++++

and in my experience not only for the tonearm torsion resistance factor but depending on the tonearm build material, a 9" arm wand has a different " sound signature " than a 12" arm wand .

In the last three years that Guillermo and I been in our self tonearm designs we made ( and still do it. ) several and different tests and one of them was to have a shoot-out with the same cartridge, different ( same build material ) length on the arm wands, very near resonance frequencies between them ( due that we use different headshell weights ).
We do it with 9", 10", 11", 12" arm wands and we find that with the 9" is a clear overall advantage ( what we can hear )but betwen 10" and 12" seems to me that exist a " threshold "/land where it is extremly dificult to discern if there is a 12" advantage in the sound reproduction quality due to the stand alone length factor.
Our findings are very interesting because our propietary tonearm build material is almost neutral ( it does not have a " sound " ).

When the build material move away from " neutrality " then the differences are more " obvious ".

We are building a 14" and 16" other ones and we will see what happen, here the challenges are a little different.

I already posted on other thread that when you are in the audio item design ( any ) we learn a lot on the subject because we " live " every design day with the: why's, how's, where's and the like.
I hope to finish our tonearm project in the next three months.

What I learn/learned through the tonearm design help me to understand and learn too on the TT " behavior ", that's why in other thread I insist/push hard on TT build materials, this factor is definitive in tonearms and TTs quality performance more than any one can imagine.

Regards and enjoy the music.
Raul.

Dear friends: I'm sure that many of us some way or the other are understanding in a best way the whole tonearm subjects on geometry/set-up.

One additional point that I want to address is one in reference on what Axel posted:

+++++ " There seems to be a MAJOR discrepancy here with some other expert Forum members that maintain that the pivot to centre-pin distance is NOT of the ULTIMATE importance .... " +++++

that is a mis-understood because the pivot to spindle distance is very important parameter in the right and precise cartridge/tonearm set-up.
No one can change this distance free-will with out alter all the other tonearm parameters.

If any one of you analize the calculations examples that I posted you can see that that distance always change and not because a free-will decision but because is a consequence of the use of te Baerwald/Lofgren/others equations.

It is a incorrect/wrong practice ttry to compensate errors somewhere changing free-will the pivot to spindle distance or changing free-will the overhang. We have to remember here that if we change the effective length the equation calculations give us a new overhang/offset angle parameters and a new pivot to spindle distance.
We can't change " free " any of those parameters with out alter the others and we must know eactly the new parameters values. Many people that goes that wrong practice forgot all these and forgot that exist a new and different offset angle too.

Of course that any one can do it if they have its own tonearm geometry equations and if not IMHO those almost free-will changes give them higher distortions results, no doubt about.

Like Dertonarm say: here it is not what anyone of us " think "/feel/hear it is pure geometry/mathematics/physics where the best we can do is FOLLOW IT to be nearer to the recording.

Regards and enjoy the music.
Raul.

I'm wrong, what we are doing is an additional arm wand of 2cm over 12", that's all.

Raul.