Tracking error distortion audibility

FWIW Maybe not on the current subject as I don't wish to debate protractor merits.
Since audibly my null seemed to be at about 128mm and since Lofgren B seems to be most correct as I don't hear inner groove distortion and both Lofgren B nulls are nearer the middle grooves, I increased my cartridge overhang and it did seem to sound better. I wouldn't suggest trial and error by ear as at least I can't be that precise with just my ear so I got out my protractor. I use the DB Systems. I found it very easy. Lofgren B did require about 1mm greater overhang and 1.000 smidgen units counterclockwise rotation.
Regarding alignment tools that require input of pivot to spindle length, I can't accurately measure that because of my arm's pivot design. For the system cited above where one uses the manufacturers pivot to spindle distance, No one drills the arm board where the tonearm maker specifies do they? Unless of course you have fixed cartridge mounting holes. If you have slotted mounting holes one should always mount your arm further from the spindle so as the maximize effective length and minimize tracking error. I've not read about this but I just assumed everyone did that.

What about alignment of the stylus to the cantilever? A misaligned stylus renders all methods discussed above (except maybe listening) null and void. They are utterly and completely useless.

Dear friends: There are two or three very interesting subjects ( that I experienced ) on what we are talking, let me to explain, example:
normally we have to align the cartridge cantilever and I find some cartridges that in static way its cantilever is not align with the cartridge body so I aligned not with the body but with the cantilever but guess what: that cartridge/cantilever when is running/dynamic state/way the cantilever is not mis-aligned from the cartridge body but it is aligned ( in " automatic " ) with the cartridge body, so I have ro re-align with the cartridge body: why is that/happen? I can't say it but it happen.

Other very important issue is that the two point protractors usually use the Baerwald/Lofgren parameters and the tonearm geometry parameters are different: VPI, Rega, Lustre, SAEC, Micro Seiki, Ikeda, etc, etc.

Why is that? are they wrong ?, certainly not IMHO those tonearm designers decide to choose different trade-offs against the Baerwald/Lofgren or other tonearm geometry parameters, so what happen when you re-align according to different geometry parameter through a different protractor like the one mentioned in this tread, easy it sounds different ( many say better, I don't agree totally with this. ).

I try several times/tonearms to go with different geometry parameters ( on the more orthodox " road ". ) and always likes me in the short time and till to know never in the long run, I always return to the manufacturer instructions/manual about.

I'm totally sure that those tonearms un-orthodox designers have a precise reasons of the why they do it in that way and IMHO everyone of them are just right and with al respect to everyone of you when you change those geometry parameters on the tonearm/cartridge alignment you are changing the designer " job/targets ", I don't do it anymore I try to follow the tonearm designer " feels ".

Regards and enjoy the music.
Raul.

Feathed, how are you verifying pivot to spindle distance?

One can adjust a cartridge to one or two null points all of their life and never get anything close to correct if the pivot to spindle distance is not dead on. This is what an arc protractor designed for a specific p2s provides the user. None of this getting "close enough". It is possible to get it dead on at a point past the spindle and at a point off the edge of the platter. That is how you know it is tracing the proper arc in the proper location. You can't do that with any other type of protractor. If you get p2s correct, aligning to the null points HAS to be more accurate regardless of which alignment style you use.

Using a good protractor is essential for proper setup. John Elison has created a superb spreadsheet to aid setup, available online in a couple of places such as Enjoy the Music (bottom of page).

Among the tools I use is a Feickert protractor for setting overhang and horizontal alignment, as a starting point. This is followed by the Feickert computer software to optimize the alignment for best performance in situ. People have used oscilloscopes for similar analysis; the Feickert program was expressly written for the purpose and gives clear visual indication of performance, enabling fine tuning of parameters such as azimuth and damping. Due to manufacturing tolerances the stylus may not be perfectly aligned in the cantilever, but this is no longer an obstacle since the software removes the guesswork.

Dealer disclaimer.