Feel Silly Asking This Question Alignment Parameters

@neonknight : I don’t know from where have you those overhang distances in the OP because the normal calculation for that P2S distance puts you almost there and at the end is that with the calculated Löfgren A overhang you have not any trouble with the null points:

Tonearm Alignment Calculator Pro - Vinyl Engine

"  its a matter of wanting to get this set up optimized. "

There are several ways to optimize a tonearm/cartridge alignment set up at the one with lower traking distotion/error is the SAT tonearm alignment that any one can use.

R.

Dear @mijostyn : " I prefer Lofgren B. Lofgren B generates less distortion...."

For many years my way of thinking was exactly yours till you fall in count that those tiny differences ( we can see in all those VE links I posted. ) and everything the same no one including a bat can distinguis in between no matter what and the best trade-offs per sé is Löfgren A.Everything the same how can you detect a difference in tracking distotion between Löfgren A and B when the measured groove to groove at each mm. change at lower than 0.01%? Changes is so tiny that we accustom to thozse changes with out detect that tiny changes.

Makes sense to you? because all of us have big imagination.

R.

@neonknight : " This document is reproduced here by kind agreement of Mark Baker at Origin Live. "

" Rega arms and Origin Live arms require mounting dimensions such that the centre of the platter to the centre of arm hole is approx 223mm plus or minus 2mm tolerance and the hole diameter for the arm is 24mm to 25mm. "

At P2S 225 distance L¨fgren B gives you 17.53 that has no consequwences in your 17.5 desired overhang.

Cartridge 2 Point Alignment Protractor (originlive.com)

You can read OL uses Löfgren A. I gave you the calculations for in one of the links.

In the other side it's easy to ask OL which kind of advantages gives its alignment against other normal alignments, I think you need to know and evaluate if is what you need or could not makes a differences.

R.

@rauliruegas Absolutely, the difference is probably not easily audible. It is a technical superiority. These technical issues do add up over an entire system, looking at 100s of small issues like this.......in theory. I do have a rather fine sounding system....I think.

@pinwa  No, that is not Zenith error, twisting the cartridge ( cantilever) is induced tracking error. Zenith error is the stylus twisted in the cantilever. Frankly, I have yet to see an example of this, although given the errors I have seen I am sure it happens. You need very strong magnification to see it which most audiophiles do not have. It is great for JR's business, the ghost in the machine. The cartridge is stupid in this regard. As long as there are two contact patches in contact with the groove the cartridge will make music. If you study the geometry of the stylus tip there would have to be a huge zenith error before it would interfere with tracking. The phase error might interfere with proper imaging, might. The cantilever out of alignment is a far more serious issue. 

@neonknight I forgot to mention. The most common mistake I see when setting up a cartridge is the technician does not neutralize the antiskating mechanism before setting the overhang and offset. This will substantially angle the cantilever when you set the stylus down. The cantilever should never change angles from its resting position even when playing a record. If it does something is wrong. 

@mijostyn : It’s inconsequential.

" Professor Erik Löfgren [6] of the Royal Institute of Technology in Stockholm, Sweden, and is the earliest work known to the author which gives an analytical treatment of tracking distortion and develops a new optimum alignment method to minimise it. Löfgren provided mathematical equations to the distortion model developed by Olney, and undertook a Fourier analysis on them. The results confirm the relationship postulated by Olney, which translates into the distortion being proportional to the tracking error and inversely proportional to the groove radius. The tracking error divided by the radius has become known as the Weighted Tracking Error (WTE). Löfgren then sought to minimise the tracking distortion by minimising the WTE. Löfgren developed an optimisation method which involved applying the minimax principle (as used by Wilson) to the WTE. The maximum level of the distortion is then represented by the slope of the tracking error graph rather than by the level of the tracking error. This method results in less tracking error at the inner grooves where the wavelengths are shorter. The introduction of this inverse radius weighting complicates the analytical solution, and Löfgren uses an approximation method which relies on the error angle being small. This is a reasonable mathematical approach, and incurs very little error. An interesting feature of the optimisation method is that the null radii will later be shown to be the same as those provided by the later authors. The optimum solution from Löfgren provides for an offset angle and overhang which minimises and equalises the three resulting WTE peaks across the record playing surface. This three-point, equal-WTE solution has continued to be applied to the present day, and I refer to this as the ’Löfgren A’ solution.

"An objection that could be raised against the [Löfgren A] calculations is that the three maximum values of the parameter δ/r (ie, WTE) are not of the same importance. A greater importance should actually be attached to the maximum at r* than to the maxima at the inner and outer recorded radii r1 and r2, first because δ/r changes only slowly in the vicinity of r*, while in contrast δ/r changes very rapidly at r1 and r2. Secondly, the inner and outer radii r1 and r2 are not necessarily utilised with each record. Because of this consideration one should permit somewhat larger values of δ/r at r1 and r2 than at r*.". Clearly, Löfgren was concerned with the extended period of slowly-changing distortion between the null radii. Thus, the central WTE (and distortion) peak should be lowered, while allowing for short periods of higher WTE (and distortion) at the inner and outer groove radii. "

In any standard calculator you can read these:

Maximum error always be: Löfgren B , Maximum distortion always be Löfgren B and Average RMS Distortion always be Löfgren A by around 0.04% that has no consequence in what you listen.

You know that there is nothing perfect and only trade-off choices. You prefer B no problem.

R.