T Bone
From your all your posts on this thread, you have obviously thought all this through, and I appreciate your comments. First let me say I ploughed through the thread prior to posting and read all the arguments with all their points, both relevant and off the wall. I also looked at related threads.
I don't have an axe to grind, other than the one called clarity, and I am the first to admit I might not be as clear as I could be at times.
To take your points:
1.
I have seen no vagueness of analysis on 12" versus 9".
Basically he doesn't say why he considers Baerwald/LofgrenA IEC a 9" as opposed to a 12" alignment - the nulls are the same - and confuses the issue with the comments regarding record radii by talking about old records. I'm not saying he's wrong, just that the two things then get connected disproportionately. What I was asking was if he saw a difference between old and new records with full sides - is that a factor.
I have old records with very long run out groove, and new ones with the opposite. What he should have been clear about at the beginning was that the issue is primarily about where the minimum radii are in any particular collection and what each person wants to do about it.
That is as you say, step one, and I agree. Average out the radii in some way, or use a deck as Nandric wittily suggested, with four arms set for different minima, or whatever. In which case there are no standards, but different nulls and you get a protractor to suit each.
You said
Standard geometry using standard assumptions does not always produce lowest possible distortion except in the case when the record has the same dimensions as the standard assumptions AND one does not prioritize low distortion in one part of the record over another.
I don't disagree. I just asked that he should have been specific rather than vague.
2. In other words, is he just saying:
"use a minimum radius of 55mm", (say, or 57 or whatever),
or is he effectively saying: "I played around with the spreadsheet and found nulls which work best with both DIN and IEC",
or is he saying
"I have a theory which says that the existing weightings are inappropriate because there is D% more distortion due the added effects of X and Y and Z, and here is what I think the weighting should be.to compensate - use this to insert into the Lofgren equations to calculate the best alignment for your record collection".
That to me, is being vague, or obtuse, deliberately or not.
I'm not looking for "new math", just asking for clarity regarding the existing old math. I have looked through the thread and admire your persistence in bringing some sort of sense to the scene, and I take all your points regarding Darkling Dert's alignment being the way it is. I don't disagree with him, or say he is wrong in what he is taking as his parameters and objectives, but until your intervention it appears that he wasn't up for clarifying things. Presumably, he had reasons for that, personal, commercial, legal "foral", who knows.
3. You said
I think all of us, including the dastardly Dertonarm, get that minute changes and ball-busting accuracy requirements for one or two of the parameters will necessitate the same accuracy requirements for ALL the geometric inputs (though inner-most groove by its very nature must have some flexibility because one does not newly align (or set up a new headshell) for every particular length).
I wasn't talking about being so anal as to change alignment for every record, nor saying that DerT wasn't concerned with accuracy, but drawing attention to the fact that he didn't share any measure of that concern in terms of how accurate was his offset angle adjustment method. As you well know, if the angle is off by half a degree, never mind more, all that precision will leave your alignment different from what was intended, and generally not in a nice way.
You said:
As an aside, as far as I can tell, the supplied lengths and angle for your signature tonearm don't match the null points noted in the manual.
The null points for all my RP1 arms as I recall, were 63.5 and 119.5. with a minimum radii of 58/146 - basically Baerwald Din, rather than IEC, as I had more records with that characteristic, and it seemed a good option - in that regard I concur with DerT. I think he is correct. And I would agree that a different alignment approach can pay dividends.
Not having seen the supplied protractor, I can only presume it was in fact like a jig so that people could set their cart perfectly straight without deviating from appropriate offset angle, and then the overhang would fall into place shown on the protractor.
I don't get this, T Bone.
No jig was supplied. The protractor was a two point, and the effective length was a nominal 230mm, the offset, a nominal 23.5degrees, with a linear offset of 91.5. Mounting distance was therefore variable as it would depend on the effective length with cartridge (see SME comments to Peterayer above)
Using the accuracy as stated, one would not have come up with the same null points as you did, which means that anyone using a protractor other than yours would have been off Baerwald by a decent bit, even if they had managed to get the offset angle and mounting distance perfect.
Could you be more specific? I'd have thought that would be more applicable to arc protractors... as long as there is play in the cartridge mount you can get a Baerwald IEC or Lofgren without any problem -just adjust angle and mounting distance as necessary. You'd need a two point protractor, though.
4.
I don't know Dertonarm, and perhaps I could dig up some info on him, if I had to (the internet is a wonderful thing, but time consuming). My point was that I don't think I should have to.
If I was selling something, I'd be happy for people to know who I was, and where I was - it's not an issue for me - although perhaps I'm just a bit behind the times and it's more acceptable now, in a forum, on ebay etc. Anyway, you knew exactly who I was, without any digging, and, by now, anyone else who wishes will know a great deal.
As to the protractor, other people challenged him on the subject, and rather than complain about being attacked, he made it. He is now offering it out.
Good for him, I hope he makes his money back, but he isn't doing anything different from a host of others who try their luck at the hifi business.
Is it more expensive than a laminated piece of cardboard? Yes. Is it for everyone or is necessary for achieving good sound? No. But neither is a gold-plated tonearm with diamonds on the headshell.
A slightly cheap shot - I don't know you and, with you, I have no beef, T Bone, but perhaps I deserve it. If I have been a bit too critical in some areas and if I've caused offence, I apologise, But reading the thread, there were some obvious things that needed to be said.
And I agree that gold plate and diamonds aren't obligatory, however, you may have given our man, Diamante Dert, an idea for a more limited edition...
