Uni-Protractor Set tonearm alignment

Dear Daniel, I promise I'll stop to tease you with so much out of topic queries any more. I've just figured out that is worthless, as it seems you avoid to answer anyway. Not that you are obliged to do that of course.

(ie): the "alternation of the skating force the tonearm can apply to the stylus/groove contact" that resulted by the twisting of the cartridge to the headshell, it does not seems a downside to me. And this is coming logically once the skating force isn't constant, we have to apply an antiskating force even to those pivoted tonearms that "apply practically zero skating force to the stylus" in order to fight this force across the whole length of the record groovies. So, it seems a neccessity and also inevitable to me as long as it is depended by the cartridge & the groovies also and not only by the tonearm. Now according to this logic, once that we have to integrate an antiskate mechanism to the tonearm, I can't see why the value of it could be in any way an indication of the tonearm's quality. We just have to apply more to those tonearms that carring a "twisted"?! cartridge on their headshells.

I'm really sorry but I just can't follow your replies, as in your posts it is impossible for me to find anything like an advice or a suggestion, no matter what the question is. I'm sure it must be a comprehension issue due to the combination of my bad English and my sciolism and so, I'm stopping right here with my apologies. Anyway thank you for your patience and your ability to stay calm with me for so long.

T Bone

I take on board all your points, and, as it happens, I agree with Dertonarm on some points. I just wish he would stop obfuscating and avoiding admitting he has completely missed the point on others.

Regarding reasons for different weighting, check out Keith Howard's piece in the features/reference section
http://www.stereophile.com

You said you couldn't get the numbers to match and something had to give. Something always does. In this case, the theoretical world. I never saw the point of giving numbers which were impractical for set up. Thirty years ago, no one set their tracking angle and the rest, to three decimals.No one does today. The numbers were rounded up for a nominal effective length of 230. The important word is "nominal". I should have perhaps laboured the point more, but that was back when tonearm geometry was perhaps better understood, and the issues concerning the choice of design - sliding vs fixed pivot, slots versus holes etc, were better appreciated.

How are you doing with the SME (or rather, sliding base) geometry? I'm going to post an explanation separately.

You said

Your point about 'just adjust angle and mounting distance as necessary' is EXACTLY right and appropriate given the imperfections we each bring to the table when we mount a tonearm/cart, but that is the art, not the science (and most of the critiques of Dertonarm's ideas and protractor on this thread are on the science, not the art, of tonearm setup, and his product I would think is specifically addressing ease of getting the art right - because the science is gotten right by anyone who gets the algebra right).

If his device makes setting up easier I'm all for it, but not if it is less accurate.

That was my reason for posting originally. He doesn't say what the accuracy of his device is, compared, for example, to a paper two point. Now I don't know how accurate a paper two point is, but I do know it is more accurate than the easier one point - two nulls are always better than one, as they allow an obvious a way of double checking. And in any case, as Dertonarm has said in the past:

But the alignment of the zero (points) is the raw basic on which everything else builds.

So, adding an arc in addition should certainly make it easier to set up (for a specific effective length) as the arc and the nulls must intersect, thus giving two opportunities to check offset.

I don't have a problem with that, I think it is a good idea.
If it is easier, great, fine, but is it more accurate...?

Hopefully, if not DerT, then someone will tell us.
J

John,
I have read the Howard piece (assuming you mean 'Arc Angles'), which I think is an appropriate intro to the subject for many people. His brief points on weightings are interesting but, they just aim at the idea, and go nowhere with it. The last time I dug around in the Stevenson articles, I did not fully understand where some of the assumptions had come from, and I remember being bothered by one in particular (stylus to 'turntable pivot distance'). I assume it is in the Baerwald so I'll have to go back and actually spend some time digging in the formulae.

I agree that accuracy is very important and should not be sacrificed by ease of use.

I'll set up using Uni-Pro's Baerwarld IEC and then recheck with my Mint protractor which is also Baerwald IEC and see if they are spot on or any differences.