Feel Silly Asking This Question Alignment Parameters

Dear @lewm @wrm57 : MINT LP disapeaed of the market and was one of the first protractor with dedicated turntable/arm, specific . Was really inexpensive.

The dedicated, one only, alignment hasd a way high limtations for the owner and for the cartridge against universal pro-tractors as the Feickert protractor.

If I will live for ever with that tonearm/TT alignment maybe no problem ( just maybe ) but it does not gives any single advantage over the universal protractors that gaves us to achieve the best quality level performance for any cartridges and tonearms combinations and or different kind of aligments. Ar the end we have try that the cartridge can shows at its best and a dedicated protractor can’s do it, probably at random but who knows.

Newcomers must know that could be a big mistage to get married with that kind of protractors and that the best " road " is a Universal alignment protractors. In the other side the OP posted that he wanted to optimize about and maybe he does not achieve it.

R.

Dear @neonknight  : According the OL information you can make the alignment with that 9.5"  El and this is what you can get and could be the best orthodox alignment shot:

https://www.vinylengine.com/tonearm_alignment_calculator_pro.php?arm1=Arm+1&l1=el&a1lv=241.3&a1=la&oh1v=&oa1v=&arm2=Lofgren+A&l2=el&a2lv=241.3&a2=la&oh2v=&oa2v=&arm3=Lofgren+B&l3=el&a3lv=241.3&a3=lb&oh3v=&oa3v=&arm4=Stevenson&l4=el&a4lv=241.3&a4=st&oh4v=&oa4v=&rs=12&rsv=&og=iec1&ogv=&ig=iec&igv=&cal=y&submit=calculate

R.

@dover : It's curious/negative that you took from my posts only what ssome way or the other you can use as a weapon.:

Iposted this information that came from VE but maybe you don't read it or let pass on purpose:

" 

 " 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. "  

So that's not my information, I only pasted and used.

R.

@dover  : No, that was finger error.

Even that the calculations for the P2S 222mm shows at that firstlink I posted and the EL calculations shows 239.3 for that P2S. Numbers says that's the correct EL not 239mm., numbers are numbers/mathematics.

OLsays in his site:  " Centre of mounting hole to centre of platter should be 222mm (plus or minus 1mm tolerance). "

It's not talking of overhang.

Now, if the P2S distance change to 221mm or 223mm over calculations at the same time changes the overhang and offset angle and the main target for any tonearm owner is to make the tonearm/cartridge/TT alignment with Accuracy and this is what I'm talking about.

Anyway, that 239mm or 9.5" stated by OL can't be achieved with the OL information.

So other that my finger error I think I'm not wrong.

Maybe what created some kind of confusion in my posts was that my " error "I wasthinking that the OPwantsit 17.5mm as overhang.

" Apparently you think its fine to set up tonearms with an accuracy of +-0.3mm "

You did it not me,so don't put words in my mouth.

R.

Dear @mijostyn  : That's not the issue. Again starting ( no matters what ) the second null point the cartridge tracking task goes harder to tracing as at the begening/medium distances in the LP grooved surface and for that reason Löfgren choosed that in the last third part of any LP the tracking distortion gone lower and that is why he named to the A solution the Optimal Optimization that's a better alignment that his side line solution B.

@lewm   " to the point where the stylus has difficulty tracing the groove accurately. "

Something like that, thank's.

R.

Dear @mijostyn  :  It's not that I prefer pivoted against LT only that today for me is the best option, that's all.

Btw, it's useless to follow the dialogue with you about Löfgren A and B because I think your never read before the over 150 pages of the 1938  Löfgren papers where you can learn which was his main target no matters if the grooves goes up to the label or not, next again part of what I posted about:

" 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. "

The B solution was only a sifde line and not his main target but to understand what I said before about the LP label you need to understand in deep Lofgren A in the WP.

Btw, the comment from that expert I posted came from 2010 .

No matters where the LP label is, just after the second null point ( inner ) the cartridge task is way more complicated and where the levels of distortions goes up and up till the last inner groove. The optimization WTE in Lófgren A permits lower distortion level where it matters the more. Take it or leave it but these is the main target/issue by Löfgren and he stated in those WP.

R.

@dover : "

Origin live Agile ( standard 9.5" arm 239mm ) has a recommended pivot to spindle distance 222mm.

Overhang for Baerwald A is 17.3mm "

I’m not wrong because I only gave neonknigth different alignment choices for his tonearm.

Who is way wrong with the numbers is not only you but OL too because 222 + 17.53 is not 239 or 9.5". One of my options that I posted puts the best number nearer to that 239 with a difference of only 0.1mm instead 0.3mm.

Anyway, numbers just do not coincide.

R.

@dover : No it’s not wrong because OL says a margin of +,- 2mm. In the other side we can change those numbers with out any negative consequence because 225 means longer EL and les distortion.

I posted the link with 222mm Löfgren A. I think you not read it not even the link of OL protractor I posted.

R.

@mijostyn : Good but we are not talking on LT tonearms.

Returning of the kind of alignment you prefer next is what an expert about ( no ofense to your knowledge level in anyway ) :

" Löfgren suggested an alternative alignment in his 1938 paper, which calls Löfgren B, but its raison d’être is different. It gives the result shown in fig.11, from which you can see that it lowers distortion over the middle portion of the disc at the expense of higher distortion toward either groove extreme, particularly the end of the disc side—an approach that just doesn’t make sense to me: "

That fig. 11 is similar to the graphs in VE calculator.

R.

@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.

@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.

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 : 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 @neonknight : If you have to stay with that 222 P2S distance and at the same time you like that overhang be 17.5mm you can get it with Löfgren A alignment making a change in the most outer groove alignment .

You can use the VE calculator that permits you to change almost any input calculation parameter and in your case you only has to choose instead than the default IEC most outer groove distance you will use 148.5mm ( custom choice ) and you achieve 17.51mm, then you are there:

Tonearm Alignment Calculator Pro - Vinyl Engine

or changing the P2S to 219 you can get this:

Tonearm Alignment Calculator Pro - Vinyl Engine

Regards and enjoy the MUSIC NOT DISTORTIONS.

R.