Uni-Protractor Set tonearm alignment

Interesting comments on changing the Effective Length input on the arm's set-up geometry?
Those with a Fidelity Research FR-64s tonearm will know that the manufacturer's recommended spindle to pivot distance is 230mm.
This is precisely the figure I used when setting mine using Baerwald geometry.
It was only when I read Dertonearm's statement that Fidelity Research "got it wrong!" that I changed the spindle to pivot distance to Dertonearm's recommended 231.5mm with an overhang of 14.5mm.
Instantly I heard a difference across the entire presentation?
More relaxed, more focused and somehow 'sweeter'?
How could this be? Was it the 'placebo' effect?
As Raul claims that our ears could not hear the differences in distortions that are indeed quite small between different geometries, why am I hearing a perceived improvement in presentation?
Shouldn't I, at the very most, only hear a difference in distortion at either the beginning or end of a record?
Perhaps Daniel could explain to me what it is I am hearing and why the change of arm geometry has caused this?

Dear T_bone: The Exel spreadsheet is very good idea.

About an increment on the EL the " land " you have to move is limited by the headshell slots and is posible that 3-4 mm makes no diffrence that you can hear.

If these kind of changes on the geometry set up beeen the only factor on the cartridge quality performance then is for sure that you can detect a minimum/tiny EL changes but there are other factors and IMHO other very important ones that a some levels preclude we can detect tiny EL changes. everything is important on cartridge set up but IMHO VTA/SRA and Azymuth makes the higher differences ( other than a matched tonearm. ).

Other that to use any of the protractors out there ( DT included. ) IMHO ( if we want to stay with mind on calm, even if we can't hear some geometry set up changes. ) a good alternative is to measure the most inner groove in our LP collection and take a choice with foundation on what are that LP collection if the 80%-90% of the Lps measures around 60mm then the IEC standard is the best choice in either Löfgreen A/Baerwald and Löfgren B and from these two if we want lower distortion at innergrooves then the choice is Löfgren A/Baerwald that additional gives you the same tracking error between null points and outer null points: this is very good compromise.

In the other side if the 80%-90% of the LPs in your collection are around 50mm or lower then you can choice between Stevenson or Löfgren A/Baerwald with non-IEC standard for the most inner grove data instead you change that input data for 50mm. I prefer this Löfgren A/baerwald that gives you sligthly ( tiny ) higher distortion that Stevenson at the very inner grooves but with lot lower distortion levels on all the remaining recorded LP area: this for me is very good compromise too.

That's why Löfgren A/Baerwald is the most used geometry set up.
IN the other side IMHO Stevenson was and is used by Japanese manufacturers because ( with all respect ) they did not a in deep analisis on the overall subject and its different alternatives, I already posted that I know this because I asked them about with no certain answers that could tell me they have in deep knowledge.

T_bone if it is true that this geometry set up cartridge/tonearm is something/subject really simple it could be very complex if we don't understand its foundation and alternatives.

I know many people don't understand yet and I don't blame any one for that. As I posted reviewers, audio distributors, tonearm designers and audio " gurus " does not understand in deep either, this is where a thread like this has a critical an important role for we improve our each one knowledge level on the whole subject.

The real value of discussions like the ones we have here and especially between DT and I IMHO always help ( one way or the other ) to lear, I can tell you for sure that I learned here too.

My attitude to " win " a discussion that I had on the past I left on the past even that sometimes you could think I want to beat DT or other person but it is not in that way, if I " insist " is because either I don't find true arguments against in the other person or because I'm challenged my own arguments/opinion till its fall/down or confirm it.

One of the best way to learn is through discussion with other people if what you move is to learn and not only who is right where you can't learn.

Regards and enjoy the music,
Raul.

Dear Halcro: The FR64 manufacturer numbers are for Stevenson IEC geometry set up ( and Mr. Ikeda don't take the exact Stevenson parameters but only an aproximation: he put for example 15mm on overhang instead the calculated number: 14.91mm. he did the same for the offset angle and pivot to spindle distance. ).

With the FR 245mm efective length and 230.09 pivot to spindle distance the Stevenson IEC calculations gives you: 0.728 on maximum distortion with 0.477 as average distortion.

If you change the pivot to spindle distance to 231.5 then the new Stevenson IEC calculations gives you: 246.324mm EL with 14.824 on overhang and maximum distortion is 0.724 an average one is 0.474.
Changing only the overhang to 14.5mm gives you a maximum distortion 0.724 with an average of 0.475.

Now for each one of this calculations the offset angle is different. The FR manufacturer offset number is 21.5° that's is greater than the 21.149° and 21.269° on those calculations.
So, if you don't change the 21.5° original/manufacturer cartridge offset angle then what you have is higher distortion levels that the ones here calculations showed.

If all this is true IMHO that you like better a higher distortions set up is not at all something weird, all the time some of us like some kind of higher distortions than lower ones.

I don't have mounted my FR right now ( its borrowed to some one that want it. ) so I can't make tests for my self.

Please do it a favor and change that near Stevenson IEC set up for Löfgren A/Baerwald as follows:

overhang 16.8mm, offset angle 22.4° and pivot to spindle distance 228.2

please test this set up and compare against the one you are using and appreciate you comeback with your comments.

Thank you in advance.

regards and enjoy the music,
raul.

Halcro, of course that you have to re-set the VTA/SRA and Azymuth for the new geometry set up. Sorry to take your time but things could be that you could like the Löfgren/Baerwald geometry. We don't know yet.

regards and enjoy the music,
Raul.

Halcro: you said that you was using 230mm pivot to spindle on Baerwald and this is for a 246.736mm on EL that is diffferent from the 245mm manufacturer number and that gives you different overhang and offset angle.

Anyway if we/you want to compare the same 246.324mm EL as with Stevenson ( at 231.5 pivot to spindle. ) then on Baerwald the overhang is 16.76mm with an offset angle 22.29°.

Regards and enjoy the music,
raul.