Uni-Protractor Set tonearm alignment

Raul,
I do not understand your question and what you are looking for in your "1984 German magazine" post. I do not know where the Nandric reference comes from. I do not know what "those FR numbers" refers to. If you want to tell me what "those FR numbers" refers to, please do. I also do not know what you are talking about when you say "I'm still waiting what I ask you before" but it may be answered below.

As to your next post, the numbers I posted for Dert63 DIN (246/14.5/20.574) were:

whole-record average of 0.42% for Dert63 and .433% for Baerwald, and 0.39% for Lofgren B. I get max TD of 0.89% for Dert63, 0.66% for Baerwald, and 1.09% for Lofgren B

The link for the Dert63 (20.574mm offset angle) DIN calculation for those parameters on the VE calculator is below:
http://www.vinylengine.com/tonearm_alignment_comparator.php?m_el=246&m_oh=14.5&m_oa=20.574&compare=d&submit=calculate
They state: 0.421% average and 0.89% max.

The link for the 245mm EL (which is nearly the same as the link you provided above - just switched to DIN rather than IEC) is
http://www.vinylengine.com/tonearm_alignment_comparator.php?m_el=245&m_oh=15&m_oa=21.5&compare=d&submit=calculate
They state 0.39% average and 1.09% max for Lofgren B and 0.443% average and 0.661% max for Baerwald.

Those numbers on the VE calculator results linked are EXACTLY as I posted. My assumptions are clearly stated. Dert63 uses 246mm EL, 14.5mm OH, and 20.574 degrees offset angle. The Baerwald and Lofgren B references use the original 245mm EL. All three assume DIN groove radii.

My recent post focuses on Dert63 rather than Dert66, that is to say on the 20.574 degree estimate (i.e. 63mm inner null point), because it gives the 20% lower max than Lofgren B, and 5% lower average than Baerwald that the deipnosophistic Dertonarm mentioned in one of his earlier posts.

If you find different numbers than mine from those links, please show them. I do not see how I can be clearer in my 'proof'. The link to the spreadsheet which would allow you to do the same calculations for average and max distortions over any portion of the modulated groove range (i.e. the inner two-thirds) is provided above.

In any case, it is pretty intuitive. Dert63 is something like a shifted Lofgren B. If you shift the Lofgren B curve towards the center, you will have higher distortion at the outer groove, and MUCH lower distortion in the inner area, and because of the shape of the Lofgren B curve, the average of the inner part will be lower with the shifted version. And as I and others have said, choosing geometry is a matter of personal priorities. The 'absolute' with any of these has to be qualified very specifically.

Dertonarm, my apologies for assuming you did not know the basis for the Dennesen design. I thought you were inquiring about that on 3/22 when you ask, " just out of curiosity - does anyone know, what calculation is used with the Dennesen Soundtraktor ?"

Then later that date you posted, "despite what some here on Audiogon did say past early winter in a deleted thread, the original Dennesen Soundtraktor is 100% Löfgren A / Baerwald IEC."

My only intent was to verify the information from the Dennesen manual and to offer a little bit of user experience with that tool.

I do continue now to wonder if Dennesen considered other alignment calculations and rejected them, or if he simple accepted Baerwald because it was the most well known?

Dear T_bone: Yes, I'm using the VE comparator IEC and DIN too for a fixed pivot to spindle distance.

IMHO we need at least one calculation data that be the same on all and any calculations, this data is: 231.5mm pivot to spindle that's is what states DT ( btw, Nandric posted that all those DT numbers comes from that magazine. I can't be sure because I don't find that German magazine from 1984. It suppose that the reviewers made and change those FR manufacturer parameters. ) and if you see and read again that comparator VE link that you already sawed you can attest that that PTS distance of 231.5mm are common for Stevenson, Löfgren B, Löfgren A/Baerwald and obviously the custom one that's where that data comes and the one DT states.

In your posts you give the average distortion values for different set ups/calculations that obviously are different from the VE where exist that common PTS data for we can compare apples with apples because in that VE comparator the Stevenson, Baerwald and Löfgren B are the " answers " against the original ( DT numbers. ) parameters with the same tonearm pivot to spindle distance.

Said all that that average distortion values are:

IEC ( OA: 20.325° ): Original/DT 0.421%, Baerwald: 0.387 and Löfgren B: 0.347.

Same OA but DIN: original 0.43%, Baerwald: =.43% and Löfgren B: 0.387%

In no one of this calculations the Original has lower overall distortions. You and any one can see/read the graphics on all those calculations to see the each one behavior's curves.

IEC ( with OA: 20.574° ): original 0.419%, Baerwald 0.387% and Löfgren B 0.347°.

DIN shows: original 0.421%, Baerwald 0.43° and Löfgren 0.387°. Only with DIN standard and only to Baerwald the original is slightly better.

Now, what could tell us all these calculations?, IMHO what some way or the other we already posted here: we can change input data and set up parameters and distortions levels change for the better or worst but even that the Löfgren A and B solutions has the best overall " answer " .

T_bone, I never states that there are no trade offs in any set up geometry approach as a fact it is this ( that exist always trade offs. ) what I suppoted and I don't think I'm supporting " absolutes " because that " absolutes " has no trade offs.

I still " trust "/support and like the Löfgren A and B solutions as the ones with very good compromises for any data we introduce in the calculations. Of course that if we introduce the wrong data then we have a wrong results.

I don't know what you think that for make comparisons at least one data must be common to all calculations/approaches: I support this single common data for comparisons.

Thank you for your time and information because help me to be aware where " things " comes and why your numbers are a little different from the VE ones that I taked to support my opinion.

I can't understand why DT don't disclosed 50 posts before along that 1984 German magazyne where I understand the whole FR information/numbers comes.

Thank you again.

regards and enjoy the music,
Raul.

Dear Raul, I assume that I quoted from 'Das Ohr' in the thread about the FR-64 S. According to the reviewers the
geometry in the user manual was not optimal and they proposed 231.5 mm spindle-pivot distance and 146mm eff. lenght. Those are the 'FR numbers' you are refering to.BTW
Dertonarm was also reviewer by 'Das Ohr' in those time so
I thought wrongly that he must be of my age. No idea if those numbers are of any help but I used them for my FR-64
already in 1984.

Regards,

Dear Nandric: Thank you, yes are the same numbers we are talking about.

Regards and enjoy the music,
Raul.