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. |
Dear T_bone: Normally the effective length does not change that input data, as I posted only if on porpose you want to change it.
The effective length is the main foundation on tonearm calculations through those known orthodox solutions ( Löfgren, Baerwald, Stevenson and the like. ) and is when you change effective length when all the other parameters calculated changed but not the other way around.
You need to read again those Dennes papers. Of course that you can manipulate/force on porpose every single input and output parameter on the geometry calculations but this is a different way/thing that IMHO is useless to discuss.
You can run an example of what happen on what you are asking: suppose that a tonearm design ( said: 270 mm on effective length. ) was designed according Löfgren B calculations and you want to make the cartridge set up with a different geometry like Baerwald or Stevenson geometry calculations for the set up, you can run this example through the " alignment calculator " tool in VE where you note that almost all the set up parameters ( including distortions level. ) calculated changed but the effective length is the same: does not changed.
regards and enjoy the music,
Raul. |
Dear T_bone: I forgot: +++++ " It appears we agree on that point (that using a different alignment than mfr.'s original design could alter resonance characteristics). " +++++
no and I can't say for sure if tha's happen till I have on " hand " white papers that prove it. What I'm sure is that two different approaches/solutions/equations calculated set up cartridge parameters give us two different distortion level performances.
I was thinking that I left clear that I don't buy speculations and normally I don't like to speculate as you.
Regards and enjoy the music,
Raul. |
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 T_bone: Of course that we always can change the EL and I posted we can.
On the other subject and due that's so simple through the different VE calculators ( thank you VE! ) when you or any owner of the DT protractor have it on hand you can take the parameters from cartridge/tonearm ( no big deal. ) where the protractor was used for the set up and use that " numbers/data " on the VE calculators and confirm if you have lower distortions over the LP recorded area against the normal calculations or against the manufacturer numbers.
In this subject we really don't have to argue/ask anything other that : after calculations shows lower distortions numbers/values or not?, easy!!!! , here the subjectivity does not count what you, me or any other person could think does not matters at all ( well always an opinion matters but you know what I mean. ) the easy VE calculations tell us the real distortions levels against other set ups.
Btw, when I talked of white papers it's only those simple calculations and that's all.
Regards and enjoy the music,
Raul. |
Dear friends: I think that is important to remember that what I'm talking over the thread and IMHO over those white papers outside is to align the cartridge stylus/cantilever where the pivoted tonearm is only a tool and a " must " for do it. From the tonearm we need to know only the effective length and that's all.
The star is the cartridge ( is the source if we don't take in count the LP it self. ) but it needs the tonearm to hold it.
Regards and enjoy the music,
Raul. |
Dear friends: IMHO any manufacturer protractor with multiple set up alternatives, like the DT protractor, should/could gives his customers the chart with the different distortions level with each set up geometry/template for the set up.
IMHO we customers need to know at least which is the distoprtion level to decide which one to use, I think there is no reason for a protractor of this type does not comes with this main and critical customer information.
Dt, what do you think? could be?, thank you in advance.
Attitudes like the VPI manufacturer that undisclose the tonearm set up parameters IMHO is wrong because we are the customers and we have the right to know about, this kind of information is not a " subject " that you can attain a patent and even if yes: which the problem? why manufacturers put on sale audio items for " blind/unable to speak " people that things are we are not " blind " and certainly we can speak to ask.
Anyway, only a thought.
Regards and enjoy the music,
Raul. |
Of course that to make comparisons the effective length must be the same because if we increment ( any increment, it does not matters how tiny. ) the EL distortions figures goes lower, the same happen when we increment the most inner groove distance on Löfgren A/B calculations.
R. |
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. |
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. |
Btw, the maximum distortion on Baerwald is 0.598 with an average one 0.390. These figures are lower than the Stevenson ones you are using by around 23% lower.
Regards and enjoy the music,
raul. |
Dear Halcro, the change to 231.5 mm mounting distance (and thus effective length, offset(slightly) and overhang does indeed result is a lower overall distortion level for about 74% of the grooved area compared to the "original" specification in the FR-60 manual/paper template of the FR-64s.
Distortion levels at the start of a 12" record are far less obvious (read: audible) and far less dangerous then they are towards the inner label.
Why so?
Because the difference in radius of the inner groove wall towards the outer groove wall increases with decreasing record radius.
Not a great situation for the stereo stylus.
This too is one of the reasons, why "average distortion" and "maximum distortion" figures for a given tonearm alignment calculation only give half the story.
Where are the maximum distortions? At the start of a record (usually with my calculations) or at the end of the grooved area (Löfgren A/Baerwald and Löfgren B).
How is the "average" determined ? By a narrow but very high maxima and a long area with low distortions ? Or by a rather long area with mid distortion level but no real high peak ?
IMHO (god - I really begin to love this phrase ... ) average and maximum distortion figures may be fine and all for some, but they do not really get to the core.
So why did you hear immediately an improvement in sound with "my" recommendation changing the FR-64s alignment?
First - you had less skating force (remember me saying that there might be additional breakdown torque with an added offset?).
Second - the not linear distortion level was less by 30% for more than 70% of the record.
Third - the FR-64s' "inner" geometry was finally matched by that alignment.
Some may think it is all just effective length and the resulting and depending parameters - offset and overhang.
IMHO ...;-) .... - that is not the complete entire model and doesn't tell all the story.
BTW - all UNI-Protractors of the 1st production run do get collected for ship off tomorrow and thursday.
Cheers,
D. |
Dear Raul,
We are all thankful for this thread
& your precious contribution in the subject. |
Dear all, the UNI-Protractor does feature on it's main frame laser engraved the inner radii for both IEC and DIN standard in a way that if you place it on the record, you can immediately read-out what is the inner groove limit of the record.
Thus giving you a secure basis to choose alignments taking into consideration the groove limit of the majority of your records.
Cheers,
D. |
Dear all, just out of curiosity - does anyone know, what calculation is used with the Dennesen Soundtraktor ?
Cheers,
D. |
Raul,
When I changed to the 231.5mm spindle to pivot dimension and 14.5mm overhang, I changed the off-set angle to compensate correctly at the null points. |
Dear Dertonarm: The original FR manufacturer numbers are totally wrong, these people IMHO wants only that the numbers appears in easy way for the customers but with out real care on the accuracy to Stevenson IEC solution and with no care on distortions. The original numbers: 245/230/15 and 21.5° don't match with any known geometry solution it does not matters changes in the input data for those calculations, makes no sense.
The " new " parameters for Stevenson IEC are better and the ones for Löfgren A/Baerwald ( that I posted to Halcro. ) are exactly the ones for this solution.
It is not true that the parameters you give Halcro that match Stevenson has lower distortions and this any one can confirm through VE calculations where we can see and " read " the diagrams/chart/graphics with the result on Stevenson/Baerwald/Löfgren curves.
Stevenson only gives a lower distortion at the inner grooves with a higher distortions all over the remaining 90% of vthe LP recorded area.
IMHO you have a misunderstood in this subject, please check not only the Dennes papers but the graphics on the curves through VE calculations.
Btw, Halcro obviously that a re-set in VTF is in order. I only want to insist that the reset on VTA/SRA and Azymuth is not only a must but critical to any comparison: accuracy in this set up parameters is a must ( desired. ) to have.
Regards and enjoy the music,
Raul. |
Dertonarm, I for one would like to know what the Dennessen is based on. Enlighten us if you know. |
Dear Genesis168, despite what some here on Audiogon did say past early winter in a deleted thread, the original Dennesen Soundtraktor is 100% Löfgren A / Baerwald IEC.
"My" calculation for the FR-64s has nothing to do with Stevenson.
The original manufacturers specs weren't all that bad ( they are close to Stevenson but did put the 2nd null point even closer to the label - apparently Isamu Ikeda did have a lot of Mercurys and early DECCA SXL in mind when he choosed that alignment ...;-) ....) , but they did not do the geometry of the FR-64s any right.
It is not enough to find the white papers and the alignment calculator in Vinylengine - it is more about understanding what is actually important in a calculation curve for a stereo record ( and yes, - it has more and slightly different requirements compared to a mono record) and where to position the 2 null-points to get the best performance.
As said before - the "common model" we find everywhere is a bit simplified and takes too little into account that we are dealing with a 3-dimensonal stereo groove here - not mono.
At least - not me.
Cheers,
D. |
Dear Halcro, to avoid any misleading info here, let me state that "my" calculation for the FR-64s gives - even with VE calculator ...;-) ..... - for the last 66% (i.e. 2/3 of the grooved area) of the record an average of 40% less distortion than Baerwald/Löfgren A IEC.
The maximum distortion with my calculation is in the lead-in groove where is is about level with Stevenson IEC.
That is about all what my calculation has in common with Stevenson........
The average "unweighted" distortion is right in between the figures of Löfgren A/Baerwald and Löfgren B.
Being very close to Löfgren B for most of the time and with approx. 45% less distortion compared to Löfgren B in the last 8-12 mm of a given record.
I "have" 5% lower "average" distortion compared to Löfgren A IEC/Baerwald and 20% less maximum distortion compared to Löfgren B (and his maximum is in the inner groove and my is at the lead-in groove).
I am perfectly fine if someone doesn't "like" my approach, but I know why I chose it and the results (if properly re-calculated in VE) do proof my idea even in simple graphs.
In any case - my approach is justified just as well as Löfgren's, Baerwald's or Stevenson's.
What a simple graph can't show, is that a distortion figure in the 1st third of a record is a completely different thing compared to the last third of the same record.
So finally I urge everybody to muse about the ever decreasing radius of a LP and what that means for the stereo-stylus.
This topic was discussed in the 1980ies and 1990ies in Germany and Japan (if I remember right ... in Japan even earlier) - the fact that you don't find any white papers about this in the web doesn't mean it wasn't done. There is a lot of information about many more core audio topics missing in the web.
Cheers,
D. |
Raul,
When I changed to the 231.5mm spindle to pivot dimension and 14.5mm overhang, I changed the off-set angle to compensate correctly at the null points.
Halcro Well, I wrote in in the FR Thread - which was deleted - to someone who wrote about 65x about "distortions". Based on some hyper prosecutions about distortions (you-know-from-whom) with Fr-64s+Dennesen+231,5mm P-to S I used my Graham Phantom II, which has an alignment System from B. Graham to adjust the cartridge precisely to a point (which one) and the alignment from cantilever is also possible. The result was identical. Spot on. For those who live in a rubber cell it is probably not easy to understand, but it is boring and a waste of time to repeat it over and o |
|
Dear Dertonarm: Please show the graphics where any one can attest what you are writing.
Taking " your " numbers ( I'm not against your approach or your numbers, I'm only questioning your statement of lower overall distortions over Löfgren A/Baerwald or LÖfgren B that till this moment you don't prove it in anyway. ) and like you say " even " with VE tools this is what we have ( graphics on the VE site. ):
I repeat that the pivot to spindle distance is 231.5mm and overhang 14.5mm ( as you stated and Halcro " running ". ), well for these numbers could fulfil we need to move a little the most inner-groove distance ( we have to select " custom " and introduce this input data in the VE calculator instead IEC or DIN. ) as follows:
for Baerwald: that distance must be: 53.82mm, this fulfil those numbers and the calculator gives it with an offset angle value: 20.967°
for Löfgren B: that distance must be: 52.39mm and in this case the VE calculator set the offset angle at 20.967°
for Stevenson: the distance must be: 59.305 ( Between IEC and DIN numbers. In the other cases the distance is sligthly lower than those standards. ) where the calculations fulfil the PTS and overhang stated with an offset angle: 20.967°.
Any one can confirm this and can confirm through the garphics not only where Baerwald or Löfgren has the lowest distortions but that that 66% of " lower distortions " from your numbers ( that like it or not are almost Stevenson. ) does not exist even that you states we can " see it through VE ".
Again: where are the graphics where any one of us can confirm what you said it? where? where?, well maybe your " body " and marketing manager could shows here one of those great pictures with those unknow graphics: could you Syntax?, I assume that your " boss/master " already shared with you that information or is that you are like a few persons that: " take it with out ask ".
As I said it I'm not against your approach and I don't want to know the foundation of that approach what we need is to see those graphics where any one can see and confirm what you posted here and that's all.
My statement is that it does not matters what you change the Baerwald/Löfgren equations are not only the only one equations out there but gives the best solutions ( are optimized solutions by mathematics and based in each criterion used. I already explained in deep somewhere in the thread.) for lower overall distortions. If some persons like " this or that " is other " game " and been a subjective one has no " weight " on this pure Objective subject because 2+2 is still 4.
Instead of following " creating " different confusion levels and even if you don't " win " nothing try to help all the people ( me in and Syntax included. ) that's reading the thread and show those graphics. Could you? , everyone is waiting for.
The other subject is that if it's true that your approach/equations can be confirmed/viewed by those graphics then maybe not only works with FR one but could works with any other tonearm and if all these is true and confirmed then all of us ( I'm sure ) IMHO will give you our in deep appreciation for that!
Btw, what you don't know because " you don't find any white papers about this in the web " is that " Graeme Dennes along the VE people had a meeting in Mars ( last year ) with the greats and better scientifics from Jupiter to analize this critical cartridge/tonearm geometry set up and the conclusions of this meeting you can read it on the VE site where they shared all the information with all of us.
" So this is the latest " technology " to cartridge/tonearm right and knowed geometry set up solution/equations.
I don't know why you was not invited because some of those " Japanese and Germans that participated on that meetings you talked where there. ".
Regards and enjoy the music,
Raul. |
Genesis, as D. apparently learned today, the Dennesen Soundtracktor was based on the Baerwald formula, as discussed in the owner instructions. They also mention the "audible affects of tangential misalignment . . . largely ignored for many years", a point Raul reminded us on.
I've owned a metal version (plastic was also available for less $) for many years. It has provided what I have considered very satisfactory alignments -- provided the arm in use clearly identifies the exact pivot point (my Kuzma Stogi Reference does), good lighting is available, I have my hand held magnifier, and my patience is good that day. ;-)
I would not attempt to use the Dennesen on any arm which does not identify the pivot point (this is critical to the exact set-up of the Soundtracktor for anyone who is not familiar with this device).
It would be interesting to learn if the Lofgren B or Stevenson alignments were considered when Dennesen decided to utilize the Baerwald? |
Dear Pryso, as D. read the Dennesen patent paper and measured the alignment spot distance to spindle center with a sliding caliper back in 1991, he knows since 20 years that the Dennesen follows Löfgren A/Baerwald IEC.
But it was certainly funny to notice that Dennesen was mistaken for Stevenson by some audiophiles. |
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). |
Dear T_bone: I'm confuse about your numbers.
In this link there is the calculations with graphics for 245mm EL:
www.vinylengine.com/tonearm_alignment_calculator.php?mv=&l=e&ev=245&i=i&c1=60.325&o=i&c2=&cal=1&submit=calculate
and don't shows your numbers. What am I missing here? before I go for your other numbers.
Could you guide me through VE calculator? which the link?, thank you.
Regards and enjoy the music,
raul. |
Or the links for your calculations if are different from the VE tools.
Thank you again.
Raul. |
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. |
Dear T_bone: Re-reading your post I found out those offset angles: 20.325/20.574 that I don't take in count ( I use the ones that gives the " natural " calculations, not forced ones. ) due that I use the VE calculator instead the comparator tool.
But I'm still missing something because this link calculations/graphics don't shows your numbers even that the input data comes from your post:
www.vinylengine.com/tonearm_alignment_comparator.php?m_el=246&m_oh=14.5&m_oa=20.325&compare=i&submit=calculate
Regards and enjoy the music,
Raul. |
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.... Kudos T_Bone |
Excellent work T-Bone, you are not just an expert on all that is good with vintage Japanese hifi.
Not sure I fully understand the maths, however you look to have proved that from your assumptions, Dert's numbers do provide a better mousetrap technically.
I am sure Dert will say how close you are.
BTW, might be a stupid question, but how do you accurately change/measure the offset for the headshell of any given alignment?
Looks like our resident expert has someone else to argue with - you :-) |
Once we cannot change the offset FOR the headshell...
...I suppose it is just a number and the only thing that we have to do, is to align the cantilever (by twisting the cartridge AT the headshell) to follow the axis of the tangent at the null point.
This particular tangent, is quite easy to designed by drawing the line from the center of the spindle to the desired null point and then we can easily find & draw the perpendicular of this line that intersects at the null point.
But I think that Daniel wants to provide a precise goniometer at the near future! |
Dear T-bone: According with Nandric those FR numbers comes from: 1984 German Magazine 'Das Ohr' that I can't find it on the net to read how comes the numbers.
I
Btw, I'm still waiting what I ask you before. Thank you.
Regards and enjoy the music,
Raul. |
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. :^) |
T_bone: because the last link using the FR numbers with the offset angle you states still shows different distortions numbers to the ones you posted.
Why is this?, I assume you have the answer. Thank you.
regards and enjoy the music,
Raul. |
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. |
Dear T_bone: Yes, I'm using the VE comparator IEC and DIN too for a fixed pivot to spindle distance.
IMHO we need at least one calculation data that be the same on all and any calculations, this data is: 231.5mm pivot to spindle that's is what states DT ( btw, Nandric posted that all those DT numbers comes from that magazine. I can't be sure because I don't find that German magazine from 1984. It suppose that the reviewers made and change those FR manufacturer parameters. ) and if you see and read again that comparator VE link that you already sawed you can attest that that PTS distance of 231.5mm are common for Stevenson, Löfgren B, Löfgren A/Baerwald and obviously the custom one that's where that data comes and the one DT states.
In your posts you give the average distortion values for different set ups/calculations that obviously are different from the VE where exist that common PTS data for we can compare apples with apples because in that VE comparator the Stevenson, Baerwald and Löfgren B are the " answers " against the original ( DT numbers. ) parameters with the same tonearm pivot to spindle distance.
Said all that that average distortion values are:
IEC ( OA: 20.325° ): Original/DT 0.421%, Baerwald: 0.387 and Löfgren B: 0.347.
Same OA but DIN: original 0.43%, Baerwald: =.43% and Löfgren B: 0.387%
In no one of this calculations the Original has lower overall distortions. You and any one can see/read the graphics on all those calculations to see the each one behavior's curves.
IEC ( with OA: 20.574° ): original 0.419%, Baerwald 0.387% and Löfgren B 0.347°.
DIN shows: original 0.421%, Baerwald 0.43° and Löfgren 0.387°. Only with DIN standard and only to Baerwald the original is slightly better.
Now, what could tell us all these calculations?, IMHO what some way or the other we already posted here: we can change input data and set up parameters and distortions levels change for the better or worst but even that the Löfgren A and B solutions has the best overall " answer " .
T_bone, I never states that there are no trade offs in any set up geometry approach as a fact it is this ( that exist always trade offs. ) what I suppoted and I don't think I'm supporting " absolutes " because that " absolutes " has no trade offs.
I still " trust "/support and like the Löfgren A and B solutions as the ones with very good compromises for any data we introduce in the calculations. Of course that if we introduce the wrong data then we have a wrong results.
I don't know what you think that for make comparisons at least one data must be common to all calculations/approaches: I support this single common data for comparisons.
Thank you for your time and information because help me to be aware where " things " comes and why your numbers are a little different from the VE ones that I taked to support my opinion.
I can't understand why DT don't disclosed 50 posts before along that 1984 German magazyne where I understand the whole FR information/numbers comes.
Thank you again.
regards and enjoy the music,
Raul. |
Dertonarm, my apologies for assuming you did not know the basis for the Dennesen design. I thought you were inquiring about that on 3/22 when you ask, " just out of curiosity - does anyone know, what calculation is used with the Dennesen Soundtraktor ?"
Then later that date you posted, "despite what some here on Audiogon did say past early winter in a deleted thread, the original Dennesen Soundtraktor is 100% Löfgren A / Baerwald IEC."
My only intent was to verify the information from the Dennesen manual and to offer a little bit of user experience with that tool.
I do continue now to wonder if Dennesen considered other alignment calculations and rejected them, or if he simple accepted Baerwald because it was the most well known? |
Dear Raul, I assume that I quoted from 'Das Ohr' in the thread about the FR-64 S. According to the reviewers the
geometry in the user manual was not optimal and they proposed 231.5 mm spindle-pivot distance and 146mm eff. lenght. Those are the 'FR numbers' you are refering to.BTW
Dertonarm was also reviewer by 'Das Ohr' in those time so
I thought wrongly that he must be of my age. No idea if those numbers are of any help but I used them for my FR-64
already in 1984.
Regards, |
Dear Nandric: Thank you, yes are the same numbers we are talking about.
Regards and enjoy the music,
Raul. |
Der T_bone: The same happen ( original with higher distortions. ) if the common data is EL ( 246mm ) instead PTS one in either IEC or DIN standards.
regards and enjoy the music,
Raul. |
Dear Pryso: +++++ " I do continue now to wonder if Dennesen considered other alignment calculations and rejected them, or if he simple accepted Baerwald because it was the most well known? " +++++
IMHO the precise and true answer only Dennesen could have it but I think that this could been take it in count for that Dennesen designer:
Löfgren A/Baerwald is the solution that gives you the lowest possible amount of tracking error at the inner, centre and outer grooves while keeping this error equal at all 3 points. This seems to me a good overall compromise.
Regards and enjoy the music,
Raul. |
Dear all, "that Dennesen designer" was Francis G. Dennesen himself, together with Richard Wilson, Roy D. Toulan Jr. and Peter Madnick.
Cheers,
D. |
Dear Pryso, no problem. My "question" was rather ironic and could easily lead to a misunderstanding. Mea culpa.
Cheers,
D. |
Dear Nandric, dear T_bone, I discussed the FR-64s alignment parameters briefly with Klaus Renner (founder and editor of DAS OHR who sadly passed away while still in his thirties in 1991/2) in the mid-1980ies.
Based on initial proposals of A. Wagner/Munich.
In the early 1990ies - long before there was a VE-calculator on the web (heck - the web weren't really there back then (at least not in the sense we see it today)!!) - I calculated it a more in-deep and extensive.
On white sheets of paper with a pen, ruler and a pair of compasses ...... archaic today.
Anyway - I do not want to lecture anyone nor do I say that everyone has to follow my proposal or idea regarding the FR-64s tonearm.
It is a proposal, it suits my needs, allows the FR-64s to show it's virtues and to my knowledge has never failed to sonically impress a FR-64s-owner once he tried it.
When I give a proposal in audio is is based on my experience, proofed it's merit, is most likely at least worth a try and generally not a balloon.
That I like to go different ways should not disqualify me from the start.
So far and where I live this is a free world (so far and in some parts ...) and everyone can choose what he/she/it likes best.
Former Prussian king Friedrich "the great" put it very nicely more than 220 years ago: "Ein jeder werde selig nach seiner Facon!".
Cheers,
D. |
