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.' |
Genesis168,
I am currently using an early 80s Pioneer turntable with early 80s Pioneer electronics (amps, pre with phono stage and headamp). They provide superlative reproduction of music. They have vanishingly low levels of distortion, and the headamp and amps are probably the quietest examples I have ever heard. And they are black too (except for the TT).
Lots of manufacturers had cheap stuff which doesn't sound great. That included mfrs from all over - not just from Japan. Some also had stuff which competes with the best out there today (and on an inflation-adjusted basis had prices to match the best of today (inflation-adjusted MSRP of the headamp would be in the range of $8-10k)). |
Perhaps it is my situation as intellectual Neanderthal, but I, for one, am willing to countenance the idea that a given tonearm design/construction may resonate differently (and therefore sound differently) if forces are applied in different ways (i.e. different offset angles than originally designed), the same way an arm may interact differently with different weight or compliance carts. This is not to say I think it would make a huge difference, but I think that given we are people who talk about getting VTF right to within a tenth of a gram, and levels matched to within a tenth of a decibel, and we change o-rings on the headshell collars, it is not too much to say that applying a LofgrenA geometry to a tonearm designed for a modified Stevenson geometry could sound differently than it would had it been designed with different angles and distances originally. I, for one, wouldn't mind hearing more if people had information, anecdotes, or theories. |
Raul,
It appears we agree on that point (that using a different alignment than mfr.'s original design could alter resonance characteristics).
As to another question floating around out there... whether applying a different geometry than original to an arm could affect effective length (and therefore affect appropriate geometry parameters for the arm (which might affect resonance characteristics)... That remains an open question... Or maybe that too is not as difficult as it seems. I will have another think about it...
Syntax, Oscar was a smart man. |
Raul,
Having read the papers, in my understanding of tonearm physics/math, there is no reason one cannot 'adjust' EL by 0.5mm and then come up with a new set of parameters derived from your preferred alignment (as long as the headshell is flexible enough (in terms of mounting holes)). It will no longer be 'official' but there should be room to play if one wants. Perhaps I have not properly understood. I will noodle it around a bit.
As to the other part, your idea of speculation and mine are obviously different. I think it speculative to assume that a change in the physics will have zero effect until a white paper tells me so. I have certainly not comcluded anything, but I am inclined to be open-minded, even without the white paper. |
Dear Raul,
Now we are getting somewhere... If you agree one can change EL on a given arm, despite what the manufacturer says should be the EL, necessarily the setup parameters will change. It should even be possible for it to sound better than normal should the EL be more appropriate than the original mfr's declared EL. Numbers could easily provide lower distortion results. Any tonearm where one creates a longer effective length than the mfr's own by the power of assumption will have lower distortion 'results'. I hope you see where this leads.
However we define 'white paper', I still think being open-minded is its own reward. 'Proven results' negate the need to be open-minded. However before that 'proof' arrives, speculation runs both ways. I choose my way and you can choose yours.
As to the suggestion that tonearm/protractor designers should provide the distortion levels for their setups, it might be useful. The problem becomes to what degree one takes it. I personally don't think most people want 9 sets of pieces of paper with each of their tonearms (3 curves - one each for DIN, IEC, and JIS standards, and possibly a fourth if the manufacturer's recommended setup results are not specifically one of the three), and definitely not 3 sets multiplied by the number of possible inner groove results (let' say 50mm-80mm every 5mm (makes 21 sets of distortion numbers per tonearm)). The best way to do so is to provide an Excel spreadsheet which contains the entire curve from 50mm to 146+mm for each of the curves, and a cell for inner groove and outer groove and the three calculations. But those exist already. If a mfr like VPI creates a non-standard mounting distance with non-standard (i.e. not one of the 'big 3') alignment curves, it would be nice of them to say it, but these things get out anyway.
In any case, the number of people who have multiple arms is limited. Among those, the number who want to fiddle with different setups for different records is relatively limited. Most want something to set and forget. And in that case, I assume that the prevailing wisdom per arm will always be caveat emptor! I do, however, encourage you to do so for your arm and template when it comes out. |
For those wondering about Dertonarm's numbers...
Using the FR-64S as a base, and the original 245mm EL, the average/peak % tracking distortion between 57.5mm and 116mm (the inner 2/3 of the record assuming a 57.5mm innermost groove (DIN standard)) using an IEC inner groove standard (i.e., setting up a tonearm for modern usage, but playing a record with a slightly closer inner groove) sampled at 1mm intervals is as follows:
CURVE Average Peak
Mfr 0.54% 0.85% (same in IEC range)
Stevenson 0.45% 0.72% (same in IEC range)
Baerwald 0.47% 0.86% (0.67% in IEC range)
Lofgren B 0.36% 1.45% (1.02% in IEC range)
If I read through Dertonarm's proposal above, using a 246mm EL and 14.5mm OH, I can come up with a number of different solutions depending on where one sets the inner groove null point (i.e. how one sets offset angle). Based on his "distortion 5% lower than average Baerwald and 20% lower max distortion than Lofgren B", it is easy to get the "5% better than Baerwald" for the whole record, but getting both that and the 20% max distortion depends on the scope of your measurement (does one measure 57.5-146 or 60-146 to find the max - it matters as the Lofgren B tracking distortion can rise a full 0.5% in those last 3mm). I will assume a DIN record but IEC setup, and offer three 'Dert' measurements, depending on where one sets the inner nullpoint.
CURVE Average Peak
Dert66 0.36% 0.98%
Dert63 0.37% 0.89%
Peaks are on the outermost groove whereas for Baerwald/LofB they are on the innermost groove (so Dert's max distortion numbers don't change much if records are longer or shorter, whereas Baerwald, and to a much greater extent Lofgren B, are much more sensitive to how small the runout is).
Offset angle for Dert66 is 20.325 degrees. Offset for Dert63 is 20.574 degrees.
On the inner 2/3 of the record, the average tracking distortion is indeed about 40% below that of Baerwald and 20% less than Lofgren B. Average unweighted distortion is where Dertonarm says it is (right between Baerwald and Lofgren B). However, I cannot get a "45% lower tracking distortion than Lofgren B in the last 8-12mm of a record. I see that the distortion compared to Lofgren B is even lower unless one counts the 60-72mm section. If one does the 57-65mm section, the distortion is 70% lower than Lofgren B.
Note that on the innermost 3mm, Lofgren B is EXTREMELY sensitive as to whether one uses IEC or DIN setup with a record which has a DIN inner groove. The inner null point moves 3mm (to be same as Dert63) from IEC to DIN, in which case the last 12mm is about 50% better than Lofgren B, which is probably close enough to Dertonarm's figures for this exercise.
Disclaimers:
1) I have not discussed this alignment, calculation thereof, or anything related to this post with anyone.
2) I simply did this to put a stop to the months of questioning. The exercise took me all of 10mins to do (given a pre-existing spreadsheet), far less time than has been spent on questioning whether the numbers come out this way.
3) I have never used this setup, but given the above results, I will certainly try.
Note: this kind of alignment should work for any tonearm to a certain extent (assuming flexibility of headshell mounting), because it is really a matter of tailoring the tracking distortion curve to the records and listening preferences one has. If one has a lot of records with a small radius inner groove and significant dynamics or significantly quiet passages in the last 10mm, this kind of 'astuce' (trick) is one which should work on many/most 'universal' tonearms (universal in this case meaning flexible mounting so as to allow significant cart movement forwards, backwards, and by angle). |
Oops. I made a few typos but it appears I cannot edit my post.
1) Note: datatables are tough to read but please use your imagination.
2) In para3, it should be "inner null point", not "inner groove null point" (guess I have inner groove on my mind...
3) I left out the third "Dert60" which is like a modified Stevenson because the benefits vs actual Stevenson or the other two are terribly significant.
4) Note that doing the algebra took 10. Figuring out how to write it took a bit longer. Hope it helps those in need of "proof" that numbers are numbers. |
Downunder, I am not so much an expert as a student who is not afraid of Excel. The math is easy. For fun and games, please try this spreadsheet. Disquisitive Dert's numbers do NOT provide a better mousetrap technically unless you WANT them to. Choice of alignment depends on priorities, not on absolutes. Lofgren B will get you the lowest average whole-record tracking distortion every time. Baerwald will get you the lowest peak whole-record tracking distortion every time. Using other configurations, like Stevenson, or Dert66 or Dert63 will get you a lower average and peak distortion within a specified section of long-playing records (the average of the inner half, and especially lower on peak distortion in the last 1.0-1.5cm or call it the last 2-4min). As to getting the offset angle set up really accurately, the only real way I can think of to do that is use a high-quality arc protractor (and a good set of eyes) where you can trace the specified arc (the one created by your setup angles), and check tangency of cantilever (or more importantly stylus orientation). Raul, I am not too familiar with the VE calculator but I will, for the sake of the first part, assume it is correct. I have just run a set of calculations using your link as a base. If we use Dert63 DIN (246/14.5/20.574) compared to a standard Baerwald or Lofgren B DIN (245mm EL), I get a 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, o.66% for Baerwald, and 1.09% for Lofgren B. These are whole record numbers, and as D suggested, the Dert63 curve looks reasonably like the Lofgren B curve except it is displaced closer in. Note that I use DIN for the calculations because it is obvious from everything that the Doctiloquent Dert has said that he is concerned with records which have smaller inner groove radii than the IEC standard 60.3mm. These would fit the observations made by the Dastardly Dert. The VE graph cannot be used to approximate "inner two-thirds" with any accuracy. I have just recalculated, using a fresh version of my spreadsheet (which I downloaded from the link above), which shows that Dert63 DIN (246/14.5/20.574) has better average tracking distortion over the inner two-thirds of the record than either Baerwald DIN 245 (33% lower) or Lofgren B (13% lower), and lower max than Lofgren B by about 20% (0.89% max (outer groove) vs 1.09% max (inner groove)). I also get an overall average DIN tracking distortion (vs Baerwald) of about 5-6%, using either Dert66 or Dert63 (the difference shifts the shape a bit inwards, lowering last centimeter peak distortion). Note to this: my spreadsheet is set up differently than the VE calculator. It would appear that the "Average" distortion on the VE calculator for IEC is calculated using the DIN min/max groove radii, not IEC. I don't see how the VE calculator gets its average tracking distortion for DIN either. I get the same max but my spreadsheet's average is lower (it does not jump nearly as much in the switch from IEC to DIN). Something may be wrong with the VE calculator to jump that much (it is as if the average calculation includes distortion in the un-modulated grooves (55-57.5mm on the graph) but the max stops at 57.5mm). Strange. I will re-check mine but in any case, my calculations would be more conservative than the VE's if it were the case (i.e. the VE calculator would probably show an even stronger improvement by using Dert63 vs Lofgren B than my numbers show). I hope this helps disembrangle and disculpate the occasionally didactic but certainly dianoetic Dertonarm. :^) |
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. |
Raul,
After this explanation, I am going to have to give up on this. I will stipulate that all the numbers you have provided above are correct. No dispute there.
I tested the original claim from many months ago (with an estimate I have labelled Dert63 above) against the original reference (245mm EL Baerwald or Lofgren). One does not, in fact, have to compare everything on a common P2S or common EL because in fact, the original claim did not.
In this thread, he made certain VERY specific and precisely qualified claims. Those claims were VERY clearly made on the basis of a certain opinion about record size (hence my use of DIN standard) and his own listening priorities (reduce distortion in the latter half of the record at the expense higher max distortion at the beginning), i.e. use a weighted distortion curve rather than an un-weighted distortion curve. Again you ask for proof. He wouldn't provide it, for what I now clearly see were good reasons not to, but I was curious, so I derived what I could based on these claims. As I have shown, each one of the claims seems to hold up when one does the math.
To my knowledge, NOBODY (not myself, Dertonarm, or anyone else) has EVER disputed the 'fact' that over a whole record, Lofgren B and Baerwald/LofA have lower average and lower equal-peak un-weighted tracking distortions than any other solutions for a given effective length. It is just math. Everyone stipulated this point long ago. Just to be safe, I repeated it.
His opinion about the qualitative aspect of tracking distortion across the record is clear. His listening priorities are clear. Based on his 'weighting', he has recommended and used something else than standard. That is his choice. As 'proven', his priorities would absolutely support use of Dert63 vs either of the Lofgrens. As you said, there are no 'absolutes' other than the math. It is some people's opinion that 'math' can be absolutely perfect in theory, and still applied wrongly sometimes.
The math stands up to support his priorities. The math stands up to support your priorities too. Everyone needs to make their own choices about priorities. I leave it there.
Kudos to Dertonarm for staying out of this. I should have as well. |
Thanks D. I think I can see why people would like it. And I agree - all it has to do is suit one's needs and work well, and it would seem to be a better solution than the template provided with the arm. It is good to be open-minded about one's own priorities and be able to question the 'establishment' standards, even if it makes you a criminal in the minds of the 'authorities' or the moral police... :^) |
John G,
A few comments...
#1) I have nothing to say on his or your comments on antiskate and SME. I have seen no vagueness of analysis on 12" vs 9". Given what you say later in your post, it is pretty obvious you have a simple explanation (but you did not give your analysis either). I think if it is obvious to you, it may also be obvious to others. It is to me. If you have additional complex analysis of the differences, please share. I think 'analysis' of 'why' old full-length records should have different innermost and outermost grooves is kind of a moot point. They are different (at least mine are). If one has looked at enough records, one may notice patterns among periods, recording companies, cutters, etc. I think that noting the difference and applying math to it to achieve better set up where desirable is easy, and I think that is what he has done. 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.
#2) I don't find him unclear on geometry issues at all. As far as I can tell, he has stipulated everything you have written. He shouldn't have to as the math does not change. He mentioned in these fora, that given his parameters and listening preferences, he had found a better way (than the manufacturer's stated geometry, or standard Baerwald geometry using manufacturer's stated effective length) to set up a particular tonearm. Others pestered him on it, and he politely refused to be harassed. The effort spent by one person in particular on harassing him about this subject could fill a small magazine issue, and may have closed down two threads. I thought it would do this thread in, but he left some hints about it, and I did some analysis to figure out Dertonarm's 'geometry' including the "weightings" you speak about. It took me about 10mins to come up with it. If you did not read the analysis above, the short version is that assumes IEC records, and is basically a cross between Stevenson's 'tilt' and Lofgren A's curve shape. It achieves lower average distortion in the place where he wants to achieve lower distortion (second half of the record), and achieves sharply lower average distortion in the last 10% of the record for long records than either of the standard setups, especially when those tonearms/carts have been set up for DIN. It is, as he has stated, entirely a matter of choice based on his record selection and his priorities on where on the record he wants to hear his distortion (or lack of it). It is decidedly not 'new math'.
#3) 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). If you read his posting history, it is blatantly obvious he shares your opinion. On the other hand, bad implementation of offset angle is bad - on any geometry on any tonearm.
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. 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. 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.
#4) If you read his posting history, you can glean a fair bit of his history (who he is, what he has done, etc). A little bit of digging and you can find more. I don't know him personally but have discovered a little on these threads and more elsewhere. Without doing the digging on you, one would not know who you are either. 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. 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.
If you have but one or two tonearms, it may not be for you. If you have a half dozen, it may be cheaper than buying a half dozen protractors specifically designed for those half dozen arms. One could obviously make one's own 'mirrored' protractor using a CAD program, printing on clear plastic and mounting that on cardboard with some aluminum foil in between. But that is beyond most people who don't have CAD design experience. I don't have anything better than SketchUp, which is kind of a PITA to use, and I figure that if I don't like mine, I can probably sell it and not lose too much money on it. And in the meantime, I will have a cheaper tonearm-specific protractor for my more than half-dozen arms than I would if I bought just one. And I will have a universal protractor which will work on other tonearms. And I expect that it will be easy to use so that my conscientious set up will take less time and back pain than it would otherwise. I know nothing of the extra goodies/modifications yet other than what he has written, so cannot comment. You could send him an email and ask him yourself. |
John,
In my case, in my #2 paragraph, I reversed DIN and IEC (Dert geometry assumes DIN records, not IEC; and his alignment for the FR-64S creates lower average tracking than using mfr specs for Lofgren A IEC). I will blame it on my lack of morning coffee :^) but I've reversed them before and I am sure I will again.
Thanks for the SME bit. I need some time (and coffee) this morning to wrap my head around one aspect of what you said. May revert. |
John,
I have read the Howard piece (assuming you mean 'Arc Angles'), which I think is an appropriate intro to the subject for many people. His brief points on weightings are interesting but, they just aim at the idea, and go nowhere with it. The last time I dug around in the Stevenson articles, I did not fully understand where some of the assumptions had come from, and I remember being bothered by one in particular (stylus to 'turntable pivot distance'). I assume it is in the Baerwald so I'll have to go back and actually spend some time digging in the formulae. |
DT and Timeltel,
Given the nature of how the tracking angle changes over the course of the record (for any arm), I would expect the skating force to fall on its way inward and then start to rise again as it moves past the peak tracking distortion area between the null points. The changes in friction coefficient (which will, of course, depend on stylus shape) would affect this, as would any changes in VTF as the cart/arm track the record. Different AS methods should actually affect the VTF 'curve' (as a function of groove radius), as should the fact that the VTA/SRA angle will actually start to get steeper on the way back in. Kind of interesting to think about...
I am assuming that one's choice of alignment (or perhaps more particularly, the location on the record of the peak tracking error between the null points) will have some effect on how much skating force ceases to tail off in the last part of the record...
I've just given myself more stuff to muddle through, obviously... |
DT,
I would have figured that different alignments altered the shape of the tracking error curve (this is indeed the critique of using a Stevenson vs a Baerwald - that the tracking error curve is "worse" than the Baerwald over the whole of the recrod) and/or tracking angle curves as functions of radius, even if ever so slightly. If they did so, would the skating force curve not change as well? |
Wrm57,
Which UNI-IEC template did you try? And was the Baerwald template IEC or DIN? (or other?) |
Wrm57,
Thanks. Not sure what the UNI-IEC is... I am curious. I will have to dig further. |
