Uni-Protractor Set tonearm alignment

Jj2468, this is a very good question. Why not playing the records the way they were cut? Due to the theroetical advantages linear trackers should dominate the market.
They do not.

First of all really good linear trackers are quite expensive, you need a precisely aligned horizontal bases to put the arm on, in most applications you need a vacuum driven guidance of the arm adding a compressor. To reach minimal friction, a precondition for linear trackers, because the cartridge moves via groove edge the total mass of the tonearm the alignment is not an easy one as one may assume.

The length of the cantilever and the compliance issue have some important impact on the interaction of tonearm and cartridge in this concept. This is with other arm concepts a little less critical, also because you have skating. With linear tracking arms you may not use all kinds of cartridges due to the friction issue which may lead to destruction of the rubber parts over time.

Taking into account all these preconditions you may reach excellent results with a linear tracker. I would not like to miss the advantages of this concept.

I, for one, wouldn't mind hearing more if people had information, anecdotes, or theories.

Hm, this is a brave idea. But it is like a walk through the Darkness without a light. Comparable with saying the word Jehova , "Prophet" or- God beware - "The Earth is round".....

The Audiophile community should be lucky to have such brave minds who do not refuse to go ahead.

Like Oscar Wilde once said:

"Be yourself; everyone else is already taken"

Or like Syntax:

There are only 2 ways of sound reproduction.
Good and none.

There is much talk about the zero points but I have not
seen any mentioned in particular. Herewith two of them which I got from Howard's article in Sterophile:
'For a modulated -groove-radius range of 56-146.3 mm, they
should be at 61.6 and 118.4 mm; or for 58-146,3mm,at 63.6
and 119.6mm.'

Regards,

Dear Jj2468, the linear tracking tonearms - in any incarnation we have seen so far from Rabco, Denessen, Goldmund, Versa Dynamics, Air Tangent, Eminent, Forsell et al -displayed mechanical issues, periphery problems and stability problems which did always crippled their undisputed tangential advantage.
Most audiophiles who ever ventured into tangential tonearms later moved to tonearms with 11" or more effective length to approach kind of "best of both worlds".
Means they minimize tangential tracking error by means of increased effective length while keeping the kind of "practicability" of the pivot tonearm.
Thus minimizing the tangential "advantage" of the linear tracking tonearm.
I have had all the above named tangential tonearms in most all their incarnations in my system in the past 30+ years.
They all were promising and were able - some more, some less - to produce great sonic results (at least for moments or short periods of time).
It were certain sonic shortcomings apparent in all these designs plus practicability issues and long-time problems for many cartridges which ultimately drove me away from tangential designs.
A 11" or 12" pivot tonearm precisely aligned leaves little place to shine for a tangential design, which always and only builds on it's zero tangential tracking error - by sacrifice of other important dynamic and mechanical parameters in a tonearm.
Cheers,
D

Dear T_bone, you hit the nail on the head. For instance any derivation from a given tonearms design inherent offset angle results in an alternation of it's mechanical model - here it results in an additional breakdown torque, which has profound effects on the skating force. There are some tonearms out there which are designed in almost 100% compliance to Löfgren A/Baerwald IEC standard (all these tonearms being 9" effective length by the way). But then there are many tonearms out there which are not. And for those it is not just about aligning to certain null-points, but also that aligning to them does alter their resulting skating force (among other effects).
Usually one would say: o.k. just make the offset angle smaller and the skating force (resulting of the offset angle) will get less.
Not so as we have a design inherent offset angle and just apply a second one by twisting the cartridge in the mounting area in a different angle.
Thus resulting in a 2nd breakdown torque.
On the other hand there are tonearms like the Talea, which do feature an offset which is "free" to be determined on first glance, but which nevertheless follows Löfgren A IEC with clear given offset angle as specified by it's manufacturer.
This all should shine an additional light on the tonearm alignment topic and why there are different calculations, different focuses and different geometries.
Cheers,
D.