Uni-Protractor Set tonearm alignment

Dear Geoch,
I know there are still some "fossile guys" out there believing they ( and so everyone) is able to aligne a tonearm by just a small piece of paper. They tell their customers or friends precise alignment is not as important as buying the right tonearm or product. Their customers are usually not very eager learning about proper alignment and its exacetly what they like to hear from 'those gurus' . " you bought the right product, don't worry at all". As long as the (analogue) world will allow herds of followers to believe in such crude philosophies we should not bother about the existance of audio afficinados never being able to distinct good from bad sound.

The (analogue) world is like it is, some good developers and failed ones.
Mostly the failing guys do have a motivation to define the world and tell the succesful developers what they seem to have done in a wrong way.

believe me, I do know producers of tonearms and even turntables who do understand the theoretical implications of proper alignment but they do not really care about it. showing images of inproper alignment may help for a better understanding of the topic - that's all.

best & fun only - Thuchan

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...

Thuchan

If Dertonarm has a reputation (whatever it may be and for whatever reason) hopefully he deserves it. That doesn't mean one should accept everything he says is correct when it patently is not, and is not a matter of opinion.

I have responded to T Bone - see above.

Regarding opinions, I may have have been a bit too straightforward in expressing some of mine, and for any offence given, I apologise. But there is no point in ignoring mistakes - I've certainly made enough of those in my life, and was the better for having them pointed out to me...

John Gordon,

at no time I said I accept everything what Dertonarm says. If you look into the many threads you are now stating from you should know this. Also discussing controversial I regard as absolutely essential, not only in this thread. I have no clue what or who is driving you.

If you do know Dertonarm from the threads and you obviously studied many, especially the threads he participated in, you may know that Dertonarm is a critical contender too but more on the content side. If you have an honest agenda you will enjoy it discussing with him, not necessarily sharing all his opinions.

best & fun only - Thuchan

John,
Thank you for taking my comments with good humor and responding politely. I took your original comments as just another shot at Dertonarm. While we are all full of ourselves sometimes (and full of sh-t other times) - myself not the least guilty - I have not found a huge amount of fault in D's intellectual approach to things. I have found more fault in the intellectual rigor, or lack thereof, of those who have attacked him in this thread (and others).

1) As to his comment on Baerwald IEC being a '9" standard', I read a different meaning into his comment - I thought it was a throwaway - a comment on fact rather than a normative statement. I will re-read it.
2) As to his reasons for recommending that one alignment (and keep in mind, it is, as far as I know, only for one particular tonearm), he has stated in this thread and others that for his longer (i.e. lower value inner groove radius) records, which are classical and have crescendos/climaxes near the end of the record, given his priorities it makes sense to have the lowest tracking distortion in the second half. I don't disagree on that point. Tracking distortion is, unfortunately, usually calculated assuming a constant velocity of signal (10cm/sec at 1000Hz for mono as per DIN 45537 (1962) and 8cm/sec for stereophonic some 20yrs later). Crescendos have a wide variety of frequencies, including timpani and bass drums, which are far lower than 1000Hz and this may therefore increase peak velocity load on the cantilever/stylus/cart motor in the inner grooves, making the practical use of a constant peak velocity across the record less relevant. If this were a universal truth about music and its placement on the record, it might behoove someone to come up with some 'new math' (neither Baerwald nor Lofgren's equations are set up to be able to accept that kind of 'new' assumption without some serious re-jiggering) to help Baerwald/Lofgren 'weight' the tracking distortion differently, and therefore come up with both different null points. But it is not, and there are enough people who are religious about Baerwald being "best" without thinking about details like this that it is a lost cause.

It is my understanding that Darkling Dert has also said something about your third point (i.e. there is D% more distortion because of factors X, Y, & Z). It is (and I paraphrase here, and I may have misunderstood) that the relative pressures on a cantilever/etc are more violent in the 60mm radius area because the groove modulations are a greater percentage of the radius than they are at 140mm. This I am still thinking about. There is a Japanese guy who has done a whole bunch of research into the finer nuances of the physics of grooves, tonearms, angles, and distortions, but I am still working my way through his stuff. I am sure I don't understand the physics here. At first glance, I would have said a constant 1000Hz signal of amplitude X across the whole record will have the same relative movement on outer groove as inner groove as far as the cantilever is concerned (when moving against the effective mass/inertia of the cart/arm), but given different relative velocity of the stylus through the groove, it may not be the case. I guess it is also possible that stylus aspect change with respect to the groove wall could affect tracking distortion dynamically, but I'm working on that - and in any case, in any practical sense, it still goes back to the earlier point about records and priorities.

3) My point here was that we all get the importance of being as exact as possible in all parameters. It is mathematically so. We can therefore stipulate it. None of us are perfect, but we all try. My comment about the RP1 parameters being inexact was simply me being pedantic and small-minded given the emphasis on exactitude of all parameters. I cannot get 230/17/23.5 on DIN (or 58/146) as shown in the manual to match 63.6/119.5 (also shown in the manual). Something has to give. Your point about 'just adjust angle and mounting distance as necessary' is EXACTLY right and appropriate given the imperfections we each bring to the table when we mount a tonearm/cart, but that is the art, not the science (and most of the critiques of Dertonarm's ideas and protractor on this thread are on the science, not the art, of tonearm setup, and his product I would think is specifically addressing ease of getting the art right - because the science is gotten right by anyone who gets the algebra right).
4) I am not sure that people should need to post their resume of qualifications before coming up with a protractor and marketing it. As you pointed out, the math has been known for decades.
Your first post here implicitly claimed an expertise that you did not pre-qualify, and I did not know who you were without digging, but you so kindly gave your name in your moniker so I went on the internet (which is, as you note, a wonderful thing) and linked your name to a tonearm, which I had heard of and seen before.

In any case, if one has to have a long and public record of producing a good product and supporting it well before one can sell one's product, then nothing would ever get done. How does anyone ever get a first product sold?

I must apologize for the bit about the gold and diamonds. Indeed it was something of a cheap shot, but likewise, you didn't know Dertonarm either. But your implication was that a 10-euro digital caliper and a regular two-point protractor would get the job done just as well for less money. I may end up disagreeing (mine has not arrived yet) after I use it (especially given that I have a few different arms at hand now) but implied in your complaint was that his object was too much money, or an unnecessary expense.

And perhaps Diamante Dert will indeed be able to come up with a Bling-Tractor® (but I, for one, won't be buying it).

I am, however, still noodling on some of the aspects of the SME issue as you brought them up. Without having drawn it out yet, my feeling is that when you change mounting distance because of shorter MH2S than assumed, you have also minutely changed required cartridge mounting angle (because your change in mounting distance is happening on a different vector, and you are therefore changing EL of the physical item (which in my very limited noodling so far, makes me think it should require a (very slightly) different offset angle). I don't know enough about SME tonearms' implicit assumptions to disagree with anyone on what the designers intended, and in any case, my experience so far is that most tonearms have enough play in the mounting parameters that one can be minutely flexible if one wants, even if the design is not meant to accommodate 'play.'