Feel Silly Asking This Question Alignment Parameters


I feel silly asking this question, but here it goes. Most of the arms I have owned over the years have came with proprietary protractors, and certain ones like the SME are really just overhang gauges. For other ones I have bought custom generated arc protractors for the specific arm. I will probably do so again with this Origin Live arm. However in the mean time i decided to set up using their provided protractor. 

When I went to install a cartridge on the table, I found I was not wild about using their protractor, so I decided to generate a Conrad H arc protractor till I made an order for an Accutrak one. What I found odd is that Lofgren A had the longest overhang at 16.8 mm and  Lofgren B at 16.3mm. The Origin Live shows 17.5 mm. Is the Rega type alignment that much different than Lofgren or Stevenson? I also noticed with the OL alignment that cartridge offset in the headshell was noticeably greater. 

What is also noticeable is the sonics of each alignment is different. To be honest, I like the overall sound of the OL alignment, but I also have this nagging feeling that it does not track as well. 

 

I always felt at this stage of my audio journey I knew how to align a cartridge. I have been doing it since I was in my 20's! Now I have a large degree of uncertainty of which alignment to choose, and what the implications are if i choose wrong. This arm is a long term keeper for me, so its a matter of wanting to get this set up optimized. 

 

Any insights you might pass along is greatly appreciated. Do have a good chuckle at my expense as it seems that I get into these moments of self doubt, and trying to find the way out of the forest of audio can be quite comical. 

neonknight

@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.

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.

Come on @rauliruegas you know darn well that I have read everything. Yes, it is true that any given frequency has a shorter wavelength as the groove speed declines, but the situation does not get serious until you are inside of 65 mm. I would guess that only 5% of the records I have go inside of 65 mm. Many do not get inside of 90mm where Lofgren B shines. If you really want low distortion at the last 10% of the record that hardly anyone uses go with UNI P2S. :-)

I am struggling with ..."any given frequency has a shorter wavelength as the groove speed declines,...."  That is from Mijo's post but he was only reiterating a quote from Raul.  Frequency and wave length are inversely and constantly related, regardless of groove speed.  For example, a 1000Hz tone always has a wave length in air of 0.32 meters. And the declining groove speed on an LP, as the stylus approaches the label, is presumably accounted for in the recording process.  I am sure the text is trying to tell us something, but what? I think it's semantics. I think it means there is less groove length per second available to encode a given frequency to the point where the stylus has difficulty tracing the groove accurately. And this does not even take into account TAE.

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.

This is poor advice.

The OP expressed the desire to use an Arc Protractor.

Anyone who professes to be an expert in tonearm set up would know that an arc protractor is designed for a given mounting distance and you’re not supposed to use an arc protractor designed for a given mounting distance with another mounting distance.

If you are going to use an arc protractor, the mounting distance must be absolutely spot on.