Time to choose: Baerwald, Lofgren, Stevenson ?

Dear @pryso : There are nothing of exceptional/new down there even than the ownner of VS said he had no explanation where comes those null points values.

Look, I posted several times and I think here too that for alignment calculations there are 3 fix parameters: effective length, most outer groove radius and most inner groove radius.
In you link Cotter used the IEC outer radius and changed the input inner groove to 66. What did it that " guru "? the same he changed the IEC radius on the inputs calculations.

Exist no " black thread " about but only manipulation of the input calculation parameters.

What did it Stevenson?, as @fleib pointed out he did not touched the outer radius but the inner one where he forces that the inner distance coincide exactly with the second null point. That's all.

If you read the Analog Planet link that was posted here, I posted there that that " black thread " discovery ( even new for MF. ) for the uni was only a manipulation of the most inner groove radius and I said it its value.

Many people puts angry with me when I use the word " ignorance " but it's tru when we don't have the rigth information we are ignorant on that and what we read could seems to us as the century's discovery when it's not.

You like it that alignment not because it's better but only that tracking error/distortions changes of surface LP position.

Regards and enjjoy the music,
R.

Dear @lewm : On your take about the Vivid floating tonearm design it's ovbious that you are just speculating about the AS issue.

"""  but the arm gets great reviews and is revered in Japan and Europe.  ""

several people when listen something diferent and especially when the audio item manufacturar touted its " great design " almost always all ( especially reviewers. ) " revered ". Sometimes like in your example is by ignorance sometimes because they like those biased diferences and sometimes those biased differences are no more than higher distortions. In that regards about the " underhung " the design has no real foundation and the manufacturer speaks only on what the listeners heard it but with out single fact on its design and why is " so good ".

Mathematics always helps and you are an advocate to. What happens with the " underhung " higher eror(distortions?

Anyway, maybe all of us have diferent opinions about and maybe no one has the rigth one. That's why exist the so many forums in the internet with so many " hot " discussions. Is part of the audio fun where all we can learn.

Regards and enjoy the music,
R.

Raul,

Appropriate to the subject line for this post there are three primary alignments commonly used, identified by the names of the men who developed them.  I jokingly referred to them as the "big 3".

My reason for commenting yesterday was to add to downunder's mention that other alignments have been put forth.  I was not suggesting The Guru method is the best, only that I tried it and found it enjoyable.  I attached a link in case anyone else might be curious to try it as well.

Peace

Lewm & Fleib:

The RS-A1 is a bit different as the cartridge is able to rotate and (possibly) maintain tangency to the groove. In Viv Lab and the Yamaha YSA-2, the cartridge is held straight and thus the cartridge will at the beginning and end of the record be at a ~10 degree angle to the groove.

Some thoughts:

1) The distortion resulting from the stylus being at an horizontal angle to the groove is 2nd harmonic, which I believe is the least harmful distortion.

2) It is not clear to me how different stylus shapes affect the distortion resulting from being at angle to the groove.

3) The calculations only cover horizontal alignment and it’s not obvious to me what the resulting distortions in the vertical part of the stereo signal are and whether these are dependent on the frequency (highly likely) and stylus shape (also highly likely). In particular, it is not clear whether these are 2nd harmonic or something else.

4) This horizontal alignment is the only kind of distortion for which I have seen a calculated estimate. Does anyone know of estimates for the distortion resulting from skating forces or vertical misalignment and whether these are 2nd harmonic or something else? I recall reading a discussion of the design of the Viv Lab where the designers seem to have been concerned about skating forces and considered the related problems worse than those related to horizontal alignment.

5) I’ve only seen one graph claiming to show the actual measured distortion from playing a test record. I came across this on the web and do not know if it is authentic. It was claimed to be from a Yamaha test of their YSA-1 (~Stevenson) and YSA-2 (straight) tonearms. Does anyone know of actual measurements of the distortions?