Uni-Protractor Set tonearm alignment

Travbrow :
"A tracing arc with a specific distortion curve should have the same geometric error and distortions regardless of the arm, cartridge stylus or if the record is stereo or mono, I thought? "
Good question!
With our restricted knowlege till now, this is a fact.
So, what is going on with Daniel's proximity ?

If those 0 points mark the places whitout any distortion
why are we not able to hear them? One should akspect some
special (Aha!)feeling 'around' them. I myself would ply
only those parts on the records because my aim is perfection.

Regards,

We all, I think, recognaze the individual right of belief
in our own hearing. So anybody is entiteld to believe in
his own ears. But to ekspect that anybody else should believe in your hearing is something totaly different. So
no wonder that only some of us use the VPI tonearms.
Regards,

Dear Nandric,

"reducing the complexity means to me not being able to deal with it"

not necessarily. reduction of complexity was and is sometimes a way of gaining new insights - one will believe or not. And it is also a survival pattern in some difficult situations enabling the individual to cope with it.

Of course you are right the psychological implications are also evident when it comes to results being feeded by personality habits avoiding or defending actions. You may conclude from special communication styles and patterns if the individual is able to deal with complexity or not, mostly using only one or two special behavior patterns showing over time. In this way most of us are not very well trained or prepared dealing with complexity.

thanks for your compliments. You are right I am a very optimistic person but having gained experience about "the real world" I do think that we need controversial discussion to some extent. This is what makes it different to the glossy magazines.

Dear Geoch, my calculations for several tonearms are based on my point of view that the last 3rd of the grooved area is more sensible to distortions and tracking error because in the 3-dimensional stereo groove the difference in angle between the inner and outer groove increases with decreasing radius.
That is creating already a difficult situation for the stylus' contact area.
Stevenson tried to solved this "stereo"-problem by simply setting the 2nd zero error at the DIN and IEC inner limit of grooved area.
Usually I aim to find a 2nd zero point between Baerwald/Löfgren A and Stevenson. Resulting in about as low average distortion as Löfgren B AND only slightly more maximum distortion compared with Baerwald/Löfgren A.
Important point IMHO is, that "my" maximum distortion figures are at the very beginning of a record - i.e. in that area, where the difference between inner and out groove wall is lowest and therefor least sensible to tracking error.
"My" idea of tangential calculation tries to get the best of both worlds while taking into account the fact that we are dealing with a 3-dimensional stereo groove here AND that the most critical (read: loudest, most dynamic, highest amplitude) passages in many genres of music do occur towards the end of a piece/movement.
So "my" calculation usually sports VERY low distortions in the last 15% of the groove.
I know what I am doing and I do know exactly why.
There is no secret here, but just a comprehensive survey and a critical look at the tonearms geometry, the stereo groove and the requirements faced with the records cut the last 5 decades.
No one has to follow my ideas nor do I postulate they are the one and only ones. I know however that they do give excellent sonic results and do take into account issues others have missed.
On the other hand, Löfgren A/Baerwald, Löfgren B and Stevenson - DIN as well as IEC - are all readily available as UNI-templates.
And there are some 9" IEC-based tonearms and small collections of modern records only (with rather long lead-out groove), where Löfgren B is certainly best.
But then there are too tonearms like a FR-64s and records like old Mercury SR, DECCA SXL, Verve and Impulse (to name just a few) which do "fare" way better with "my" calculation.

The UNI-Protractor is an universal precision positioning and alignment instrument. Independent whether you use "my" calculation for a few specific tonearms or whether you go for any of the "standard" calculations. Those are all options one can choose or dismiss.
You may noted, that I have not postulated a "Dertonarm"-alignment curve.
I only did some individual calculations for some specific tonearm designs.
That's it. Because generalization isn't always preferable.
I for one are neither on a crusade nor do I preach to follow my point of view only.
I have designed an instrument the serious audiophile can use with as broad a choice of options as possible.
Nothing more - but nothing less.
Hope I could clarify the point.
Cheers,
D.