Uni-Protractor Set tonearm alignment

My mistake. If we take a effective length say 260mm and the inner groove at 50mm ( 5cms. ) Löfgren B calculation gives 1.3% and Löfgren " A " 0.8% and this is an extreme case at inner grooves that we don't find very often.

Now, if we change the data input to force better " figures " at inner groove that could be in detriment of higher distortions in the other 90% of the remaining LP grooves. Our today LOMC cartridges are better trackers than many vintages and the MM/MI ones are champions on this regards so I can't see that " dramatic problem " you states because I just tested a recording with almost no blank grooves at the end and with the XV-1s I can't detect a higher distortion level and neither with the 20SS .

To much " cream on your bananas ".

Regards and enjoy the music,
Raul.

and that figures of distortion were at the last inner groove, the last one.

Raul.

Dear all, I would like to add, that in professional audio and engineering - at least here in "old" europe - the discussion about Löfgren, Baerwald etc. is long dead.
Löfgren and Baerwald did their calculations based on mono pick-ups and in a time when modern microgroove records were an idea of the far future.
A mono stylus has VERY different tracking conditions compared to a modern stereo stylus. Stevenson took this into account first and recognized the dangerous conditions towards the inner groove. In later years Rother, Kishimi and others further commented about this.
Among all these later (read: stereo era) engineers diving into the topic of tonearm calculation it was without question, that different tonearm geometries required different calculations.
It is always about effective length, overhang and offset angle. But it is also about grooved area, increasing diameter and resulting increasing difference between inner and outer groove wall, importance of lower geometrical based distortions in area of divergent tracking conditions.
It is all geometry, but for Löfgren and Baerwald (as a direct result of their time and the limited requirements) it was only a 2-dimensional model.
But a stereo groove is a 3-dimensional model and a very tricky one in the last 3rd of a grooved 12" record.
To understand completely what is going on, one must first look and comprehend the whole model - not just a simplified one without the most critical parameters.
This is true in tonearm calculation and as well in tonearm construction.
Cheers,
D.

Tha's means at the last 1 seg. and not last 2-4 minutes as you states.

Regards and enjoy the music,
Raul.

Dear Dertonarm: +++++ " Löfgren tried to minimize distortion over as large an area of the record as possible. He did so at the expense of the last and most critical inch of the groove, where the distortion level of his calculation sky rocket. "

this is a misunderstood, that's why exists Löfgren A and B where the highest diustortion at the last inner groove is different been lower on the Löfgren A solution.
So we have choices here at Löfgren's " house ".

Regards and enjoy the music,
Raul.