Tracking error distortion audibility

"Feathed, how are you verifying pivot to spindle distance?"
Dan_ed
Unless one needs the distance for making an alignment device, the pivot to spindle distance is of no relevance at all.

I think we can all agree that alignment is difficult to get spot on and visual means have many inherent inaccuracies. To me this screams out for verification with a test record and instrumentation. I would think it possible to measure the distortion and confirm the positions of the nulls. You can then position them to agree with whatever formula you prefer or fine tune in combination with listening tests. I thought I remembered 20 years or more ago one could bring his or her table to a dealer and they would analyze the output to assess alignment. Did or does such a thing exist?

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.

For this discussion ignore the arc protractors. Universal protractors work for various spindle to mounting hole distances correct. If you have slotted headshell mounting holes you can adjust cartridge angle and overhang correct. If you drill your mounting board hole further from the spindle than manufacturers specs, simpling slide the cartridge closer to the end of the tonearm and adjust angle accordingly. You get the exact equivalent of a longer effective length tonearm. You obviously need to allow for slight differences in mounting hole to stylus geo in case you change cartridges but they vary only slightly. Brooks Burdan (sp) explained this to me 20 some years ago. It's so simple I just assumed everyone did this. I've never given it a second thought.

Thom @ Galibier,
WOW!
I'm sure any competent person would not make the errors you cite above as reasons to not deviate from manufacturers set-up, certainly not Brooks. I understood him to mean increasing effective arm length with slotted head shell models is a trick he uses with no downside. I assumed it was commonly used by experience turntable techs. I am sorry if I misunderstood but it seemed pretty clear to me what he meant. You might have understood something different but I don't recall you being present during our conversation although I might be mistaken as you indicate you heard it with great clarity "I'm sure he was arguing.....".
I am glad even happy that you like your protractor. What is your reference that verifies your protractor's set-up? What do you use to verify the stylus is perfectly aligned to the cantilever? Your protractor?

Thom,
Your longer effective length calulations show lower distortion and there is NO downside. You just proved the point. You claim to respect Brooks and you don't know everything yet you will
"set him straight".

Raul,
Not mounting a cartridge exactly where a manufacturer's direction say is not disrespecting the designer at all. The arm manufacturer has to allow for inaccurate drilling of the mounting board and has to accommodate all possible cartridges. I bet all designers would applaud taking the effort to tweak the most performance out of their arm. I'm not insisting anyone has to do this. You, like the manufacturer may want to drill in the middle of the range in case of a slight error during the drilling or in case you later wish to sell the table to someone with a very odd cartridge. I very much doubt the increase in length will make a significant improvement but why not optimized all you can?

Thom,
I beleive Raul is of the option that if a designer approved an alternative drilling option he or she would explicitly state that. I on the other hand beleive the presence of a slotted headshell is explicit approval to tweak. I completely respect his choice.
You are obviously quite intelligent, knowledgeable and articulate. You know perfectly well that a cartridge can be moved forward without encountering any of the issues you raise. Quit being silly. You seem to be simply trolling for an argument. I have finally recognized that and will no longer read your arrogant, condescending and offense posts.
Good Bye and good luck.