UNI-DIN Versus Löfgren B Just to Clarify

In the Rocky Mountain Wrap Up I wrote about the UNI-DIN curve versus Löfgren but a picture (or a graph in this case prepared by WAM Engineering's Wally Malewicz) is worth a 1000 words.

So to make sure you clearly understand what you are seeing: the lead in groove (represented by the shaded area) is to the right and the lead out groove (represented by the larger shaded area) is the left.

The "null" points are where the lines touch the graph's horizontal axis. So as you can see, the Löfgren "B" null points (where the stylus is tangential to the groove and therefore there is 0 LTE (lateral tracking error) are at 70.3mm and 117.2mm. The null points for Löfgren "A" (identical to Baerwald) are at 66.0mm and 120.9mm. The null points for UNI-DIN are at 63.3mm and 112.5mm. The Stevenson curve is shown in green

So what does this mean in practical terms? As you can see distortion is relatively high and the very beginning of the record for all curves, but plummets dramatically for all curves to the first null point. However Löfgren "B" distortion (and Stevenson) is lower than UNI-DIN for that portion of the groove surface and UNI-DIN's first null point is almost 5mm beyond Löfgren "B"'s first null. From 115mm to 97mm UNI-DIN's THD (total harmonic distortion) is lower than any of the other curves, but it is a relatively narrow area compared to the 97mm to 67mm segment where Löfgren "B" is considerably lower then UNI-DIN and Löfgren "A" (Baerwald) and especially Stevenson.

Beyond the second "null" points for all of these curves distortion dramatically rises but note that while Löfgren "B"'s second null point is a full 7mm before UNI-DIN's and therefore the distortion begins to rise well earlier than UNI-DIN's, UNI-DIN's distortion is way higher at that point and the two only meet (one rising, one falling) at the 67mm point. Still it is true that Löfgren's distortion toward the very end of a typical side is well higher than UNI-DIN's and as you can also see, Stevenson's distortion is plunging toward's the end of the side and only begins rising beyond the theoretical end of the side, which is why it is suggested (by some) for people who mostly play classical music.

However, given the far higher distortion over a larger swath of groove territory is that a worthwhile trade-off? I am not in the habit of asking questions and answering them for you so you tell me! My understanding is that the Rega paper overhang gauge is the Stevenson aligning or close to it. If you listen mostly to rock and pop music does the Stevenson curve make sense for you? Here I will answer the question because there's not doubt about the answer: NO!

Now as between UNI-DIN and Löfgren "B" please decide for yourself. My decision is to go with Löfgren "B" but I'm here to give you the facts, not here to tell you which alignment to choose. That is up to you. Keep in mind that compared to the distortions added by the rest of your system, my opinion is that all of these curves produce less.

COMMENTS
SpinMark3313's picture

Michael: For years I've used the classic DB Systems protractor which appears to use the Lofgren A curve.
Looks to me as though trying Lofgren B would be a worthwhile effort. Any recommendations for a low cost Lofgren B based protractor?

Michael Fremer's picture
How much?
SpinMark3313's picture

$100 or less - reasonable? Possible? Online printable versions are available it seems, but I'm a little hesitant to trust the accuracy / tolerances all the way through the print process at home...

Todd Lainhart's picture

I've been using this template. My setup sounds great with 'A'. It does 'A', 'B', and some others.

http://www.vinylengine.com/turntable_forum/viewtopic.php?f=19&t=16849

Ortofan's picture

...where does (the distortion from) lateral tracking error rate?
For example, in a certain price category, one could choose from pivoted tonearms from SME (cast magnesium) or VPI (3D printed composite) OR a tangential tracker from Clearaudio (aluminum and glass). Is tonearm material and bearing quality more important or are they trumped by the lower distortion from linear tracking?

JohnnyCanuck's picture

I've been in this hobby for over 40 years now and I don't think there has been a definitive answer to your question in all that time. You'll find both good and bad examples in all the areas you mention.

Michael Fremer's picture
Obviously tone arm material, rigidity, damping, bearing tightness, etc. is very important as the files comparing VPI's printed and metal arms reveal. Everything counts but if you set up 9" or 12" arms using the same geometry, that is one fewer variable to consider. I am not convinced "linear" tracking arms necessarily produce lower distortion. Most of them appear to be tracking "linear"-ly but are actually "crabbing" their way across the record, producing a series of tiny arcs, each of which probably has more LTE than a well set up pivoted arm. Dragging a large horizontal mass across the record surface is hardly an ideal way to play a record and that goes doubly so for air bearing arms where the bearing is stationary and the rail moves. Yes, they work (all of these arms 'work') but a tiny cantilever essentially dragging a high mass across a record surface is hardly an ideal situation. The Clearaudio approach lowers the arm mass but in order to get the vertical resonant frequency in the desired 8-12Hz region, requires a high mass cartridge hanging off the end, which is why Clearudio's Goldfinger is so massive. But then you're back to dragging a high mass across the record. My opinion (and it is just one person's opinion) is that, overall, pivoted arms make the most sense—and I've owned E.T. 1 and E.T. 2 arms as well as Andy Payor's linear tracker, which I think is demonstrably the finest air bearing arm ever made. As I wrote, I think the amount of distortion added by LTE is still less than the total contributed by the rest of the system. Last night I was up until 3AM spinning vinyl and I didn't hear "distortion". If it was there, it made for damn pleasing listening!
isaacrivera's picture

This graph is of much help. It illustrates clearly the differences between curves that I have been reading about, but are hard to grasp when written. My protractor, a SMARTractor, has null points for Lofgren B DIN and IEC. What are the differences and which are we referring to in this post?

isaacrivera's picture

I meant Lofgren B DIN and Lofgren B IEC.

Michael Fremer's picture
Those curves compensate for later groove area standards (lead in and out points) proposed and/or implemented by IEC (International Electrotechnical Commission) and DIN (German Institute for Standardization). However in the real world, cutting engineers tend to begin and end a side as they wish so as far I am concerned the standard Löfgren geometry rules. But as I wrote, choose your fave!
isaacrivera's picture

My protractor, a SMARTractor, which I think you have stated is what you use, has Löfgren A/B DIN and Löfgren A/D IEC. That was my question, which of the 2 curves is the "standard"?

Michael Fremer's picture
None are "standard", Löfgren "B" DIN is "traditional"
PeterPani's picture

I guess, the curves refer to a 9" arm length. Would be interesting to see also the curves for 12" for comparison how much lower realtive overall distortion is with 12".

Michael Fremer's picture
Yes the distortion is somewhat lower and we should post the curves and distortion differential between 9" and 12" arms but there are other considerations. For one if your set up is at all off, the longer arm will actually MAGNIFY and error and end up producing greater distortion than would the same error on a 9" set-up. Then there are the issues of rigidity and responsiveness (moment of inertia). All things being equal the longer arm would be better but all things are rarely if ever equal!
SimonH's picture

Yet another fascinating post - thank you - I do however have some questions and I feel a template and survey coming on to measure the radius of the inside grooves of my records.
Questions that are making my brain hurt
1) I can't see a pattern in the graphs - see 2
2) How can you the second null point be different if the first is the same unless you are comparing different arm lengths or different cartridge rotation angle from pivot point?
3) How does the SME arm with SME template compare? and are there any alternatives for SME set up?

Brilliant brain teaser on a groggy Sunday Morning

Michael Fremer's picture
Not sure what "pattern" you are looking for in the graphs. The geometric solutions worked out by the various individuals produce those results. Remember that each one puts the stylus tip at a different distance from the pivot point, thus producing a different "overhang". That different position produces the two differing null points. All of these geometries are based on a right angled triangular relationship that my mathlexia prevents me from delving into here! Most arms are designed to have a fixed effective length and offset angle specified by the designer but since cartridge mounting holes differ as do cantilever lengths, the only way to assure compatibility with a wide variety of cartridges is to have slots in the headshell that allow both fore and aft movement and twisting movement to adjust zenith angle. SME takes a different approach that locks the cartridge into a head shell with no movement allowed fore and aft or around the zenith axis (twisting in headshell). In the SME system the pivot to spindle distance varies to set overhang. In the fixed effective length model that SME uses, the head shell angle is also fixed because of the lack of slots means no cartridge twisting. When the effective length increases it changes the actual cartridge offset angle though no twisting in the head shell is involved. The SME V's geometry is Löfgren A/IEC but if you want to try "B"/IEC just slide the arm base forward about .5mm—you can't re-adjust the offset angle but there's no need to. Because SME doesn't slot even one of the head shell holes, you are limited in what other geometries you can try, though often there's sufficient "play" in the head shell to twist the cartridge to correctly set the linear offset angle....
Oksana's picture

First Mikey, as I mentioned a few years back when I was able to purchase some seriously nice equipment, I tried to purchase Wally's tools. I emailed and telephoned his company several times with no response. So it is always frustrating to read that he has these cool tools and test results that you have access to, but not at least me. I don't know if anyone else has ever been able to purchase any of Wally's stuff.
I forget who makes the etched glass protractor you use on your setup Dvd. I have the Fiekert, (about 4 years old, there is a newer version), one that comes with the Hi-Fi News test Lp, a MoFi geodisc, and the spindle adapter with cartridge alignment tool that comes with the Graham Phantom Supreme. I cannot state with authority which one is better.

Michael Fremer's picture
The one on the DVD is from Wally. Mint in Hong Kong makes good ones etched on glass. I am hoping that with the formation of the ASF we will open a reliable Wally Tool pipeline for both certified setup pros and consumers alike.
VirginVinyl's picture

I've had a same situation with the Wally Character. On the phone with him then he wanted me to call him back. It's a complete Joke. The guy is a crook And I know people that have paid for the shipment of protractor and gadgets and haven't been received anything. Also on the Vinyl forum several people have mention similar dealing with this Wally Character. Mikey why do you promote this guy when he is clearly ripping off people and asking people to send money to him and not shipping the product. You can be on the fence and prey on consumers. Mikey I find it hard to follow you DVD when you are using Wally's stuff. I wish you would start using tools that are available to the general public when you demonstrating setup. I have a VPI 3 and it doesn't come with a Wally skater or a mirror like protractor. It comes with a own protractor would it have been more productive to use the VPI protractor (I believe it's a

Michael Fremer's picture
Wally has had some health issues, which does not condone bad behavior and I've done what I could to rectify deals gone badly. I've gotten all of the ones to which I've been alerted resolved to everyone's satisfaction. However I don't think Wally is a purposeful "rip-off". He's not got a bad bone in his body as they say. However his arc-ed tools are still very useful for demonstrating overhang so I will continue to use them. Whatever Wally's issues, he knows his stuff and without the above visual that he was kind enough to produce and let me use, illustrating the distortion curves of the various alignments would have been very difficult. If you watched the VPI set up on the DVD you will see that a corroborated the accuracy of VPI's supplied one point protractor with the result I got with Wally's tool.
VirginVinyl's picture

I've had a same situation with the Wally Character. On the phone with him then he wanted me to call him back. It's a complete Joke. The guy is a crook And I know people that have paid for the shipment of protractor and gadgets and haven't been received anything. Also on the Vinyl forum several people have mention similar dealing with this Wally Character. Mikey why do you promote this guy when he is clearly ripping off people and asking people to send money to him and not shipping the product. You can be on the fence and prey on consumers. Mikey I find it hard to follow you DVD when you are using Wally's stuff. I wish you would start using tools that are available to the general public when you demonstrating setup. I have a VPI 3 and it doesn't come with a Wally skater or a mirror like protractor. It comes with a own protractor would it have been more productive to use the VPI protractor (I believe it's a

virtualbryan's picture

So it looks like Lofgren B would be a strong winner on records with short sides like many of the 45 RPM reissues.

Michael Fremer's picture
I think it's the overall winner but especially if you're 'out' before the upswing.
carlc's picture

I have the Mint protractor from Yip in Hong Kong (Stevenson) as well as a Ken Willis protractor that has all the alignments; I've used it on a Rega p1, P3-24, Rp1, P5 and finally my new Rp8. I've tried out the Baerwald, Loefgren and stevenson alignments with multiple cartridges and have to say that I could never hear a difference between them in the end - My Ortofon 2m Blue had trouble in certain spots (the same ones) no matter which one I used and my Dynavector 20x2 tracks everything without issue with all the alignments. I like the Mint protractor because it seems most precise, so it's been Stevenson, which is closest I think to Rega's own geometry.

audiof001's picture

I'm running my homemade WT clone 12" arm with underhang and enjoying it quite a lit. Minimal skating effect and great sound. No real desire to overhang that arm ever again.

Michael Fremer's picture
In truth the notion that "underhang" produces minimal skating is an easily disprovable myth. However, it does produce additional LTE. In fact, the increased non-tangency produces increased skating forces that to a great degree cancel out whatever benefit is gained by reducing or eliminating the offset angle. But as I wrote, whatever you like! That's what's great about this hobby....
audiof001's picture

Thanks for the response. I made my WT 12" clone completely adjustable (even arm length to pivot), positionable and removable. When I position it for overhang there are audible effects - a skip per side and what sounds like record wear (my records sounded old and in need of replacement) - that appear totally gone to my ear when tracking using the underhang method. I'll be re-wiring it again shortly and installing my final headshell and I'll test it with overhang again.

tresaino's picture

Hi Michael, fully agree on Löfgren B as the best choice - even more so with 12 inch arms as long as everything is set up and measured correctly. I had the Smartractor but had a number of issues with it and sold it again (we talked about it briefly in Munich).

An easy to use and cheap protractor is Ken Willis' AccuTrak, www.accutrak.us, but it is custom made for specific arms hence not universal. I got three, one for each arm, still cheap. And finally, Wally is a great guy and he knows his stuff.

Oksana's picture

Is that a normal occurrence for the Ortofon? I was thinking of an Ortofon for a second cartridge and hadn't read that before.

carlc's picture

On my arm and table it tracked well for the majority of albums - I could never completely get rid of IGD on some albums and there would be some distortion here and there other places once in a while. It's a good cartridge, but I went to a sae 1000lt and then the dyna 20x2 both of which which tracked a lot better for me.

Dorian Workman's picture

I use Yip's best tractor from Honk Hong with my VPI Traveler and Ortofon 2M Black. It took me a long time (multiple hour-long sessions) to get it dialed right in, but now I hear zero distortion across the whole record. The music simply sounds like music.

Dorian Workman's picture

Plus in all my dealings with Yip he always replied promptly, professionally and courteously.

Chris F's picture

Another +1 for the Mint LP protractor. I have one for my VPI Classic and although it's a painstaking effort the sonic results of exactly nailing the geometry are well worth it.

Yip is a good guy to deal with.

Matthew.852's picture

i would like to get Yip's protractor. Can you post his contact info. Thanks.

Todd Lainhart's picture
Matthew.852's picture

i would like to get Yip's protractor. Can you post his contact info. Thanks.

Neverenough's picture

Mr. Fremer,
It seems to me that linear tracking arms can be designed to meet the necessary requirements and provide the ideal solution. Mass (linear) or inertia (rotary) are factors when things need to accelerate. For movement in the plane parallel to the record, the grooves will create the acceleration which will vary depending on the radius from the center of the record (for the most part ignoring variable groove width). Anti-skate helps to balance this for rotary just as a bias spring or servo-controller does for linear. The amount of 'crabbing' from a linear is nil WRT to THD for a rotary (unless the bearing/controller design is crap). There's no particular reason that a linear arm can't be low mass. However getting a linear bearing to behave smoothly is usually the challenge which is why air bearings are used. I think if as much effort were put into linear trackers, the TT industry could create some very cost effective solutions that meet the resonance requirements (8-12hz) as well. Maybe we can resurrect the engineers from Nakamichi who developed the Dragon auto-azimuth controller and put them to task on this.

--Dale

Michael Fremer's picture
Very difficult to get equal mass in the vertical and horizontal directions and therefore to achieve the same resonant frequency in both directions. Air bearings have their own sets of issues...such as going from high pressure in the bearing's "work zone" to ambient air pressure at the annular gap (think of a balloon you blow up and let go of)... (etc.)
thebullfrog's picture

Thank you Mr. Fremer for finally interpreting that tonearm geometry graph! Now that you explain it, I see it wasn't that difficult to read, but I'll be damned if I knew how to interpret them before.

Also...I have used the MintLP protractor and have had good results with it. It does take an inordinate amount of time to get it down though. However, for a few bucks more, the Dr. Feickhert updated protractor is so incredible easy to use, it's almost fun to try different tonearm setups. Just my opinion of course.

alphaGT62's picture

I spent some time years back downloading alignment protractors and testing them on my Project table I had at that time. Sorry but I don't recall the exact address where I found most of them. I see that Vinylengine has some of the most popular ones. But first off, if one wants to get by cheap, downloading a template is the way to go, but great care must be taken to get a decent one made. First off, I used thick presentation grade paper, and a quarter inch hole punch with a clear top, so you can see the center. And, if the print off does not have a reference ruler on it, then you just can't trust it. I had to play with the exact sizing of the printout to make that reference ruler come out exactly to scale. But, my findings back then were that the Lofgren B sounded best on my setup. So it's great to be vendiicated by your graph!

Since then I've moved up to a better 'table and also I used the VPI template that came with it. I'm not sure how their template compares to the Lofgren B? But I figured I wasn't going to second guess the maker of the arm/'table. But I have to agree with you that the distortion level differences shown in the graph are minimal. And getting your nul points set is a very good starting point, but once set, I found greater differences in sound by carefully adjusting the VTF and VTA to ear. Observing your styls with a magnifier and getting it close to manufacturer's recommended angles as best you can, and then making minor changes by ear, has brought my analog setup to the next level. So, setting your nul points and squaring up your cartridge is only the first step in getting the most from your cartridge. To me, anyway. Since you can't control where record makers put their lead in and lead out grooves, all we can do is try to keep distortion as low as we can between the nul's.

Please correct me if I'm confused. It has been known to happen.

And just to try and answer one commenter's question: How can a tonearm have two points of being square to the grooves? That is due to the way the headshell is skewed on the end of the tonearm. If the tonearm were straight, and the cartridge straight in line with it, then there would be only one nul point, or place where the needle was square to the grooves. But the way the headshell is offset, allows it to find two points where it will be square to the tangent of the circle, which is the record. Notice that they are not square in line, you must move the platter a short ways to find the second nul. Because the centerline of the cartridge is offset from the pivot point of the arm, it allows that centerline of the cartridge to find a tangent on two circles, one large and one small. I don't know if that clears anything up? Or only serves to confuse? But hey I tried. Anyone else care to take a stab at it? Most important thing to know is that it works, the designers of modern record players were some pretty smart cookies!

Ohjoy50's picture

From my observation, although the Loefren B initially looks like it has the least amount of distortion across most of the record surface, it has the highest amount toward the end of the record. Seems to me the Uni-din has very little at the end of the record, and is fairly close to the Loefgren B across the whole record. So don't you think then that the Uni-din then has the least overall distortion ? Am I not looking at the graph correctly ?

Guess I will have to try both and buy a alignment protractor that does them both or all.

Have you played with the SMARTtractor ?

http://www.youtube.com/watch?v=oXQcdFF_Dro&feature=youtu.be

Looks very cool, very tempted to buy one just a bit pricy.
Measures spindle to pivot length accurately, sweet.

Kevin

Michael Fremer's picture
I reviewed it in detail in Stereophile some time ago. Gave it a good review with one important caveat: if you don't get the pivot to spindle distance correct, your results will be off. Many arms do not give you an exact reference position for the horizontal bearing, which is critical for getting pivot to spindle distance correct. For instance: Graham and Rega to name two....as for UNIDIN versus Löfgren: the latter's distortion is lower by a considerable amount across most of the record. Yes Löfgren's is higher at the end of the record but many if not most records are over before the distortion gets too high plus there are other issues near the record's end that are problematic regardless of alignment. These are personal choices in the end, which is why I don't try to tell anyone which is "best". If your arm allows you to easily locate the vertical bearing, the SMARTractor is a terrific tool.
silviajulieta's picture

Hi M.: You said: """ SMARTractor is a terrific tool """

I would like to know why or against what. The MINTLP protractor is unexpensive, accurate and with out caveats. With out knowing your arguments for me the MINTLP is a true " terrific tool ".

What do you think?

Greetings.

Ohjoy50's picture

Thanks for the heads up on the review. Usually the better tonearms give you the spindle to pivot distance, although its not always easy to determine exactly like you said on some arms. I have an original well tempered labs classic, hoping to find a reference version with adjustable damping etc. Not real easy to determine its pivot point either. As for the unidin vs lofgren I wasn't sure how much of the last part of the record it starts to distort, good to know, thanks.

SteveRB's picture

All records start at the edge, more or less...

Some records just don't have tracks all the way to the label. Makes sense then to optimize alignment for the first 90% of the side, the last 10% may not even be there...

Michael Fremer's picture
Is correct! It's always a compromise no matter what...
silviajulieta's picture

Dear M./friends: """ So what does this mean in practical terms? """

IMHO and for every one first we have to understand the whole theory/subject in tonearm/cartridge alignment or kind of alignments:

- Baerwald, Stevenson, Bauer, Pisha and many more kind of alignments were based/foundation in the work made it in 1938 by LÖFGREN and his solutions through his calculations/equations where the object was and is to calculate the overhang and offset angle in any tonearm/cartridge combination. These are the main outputs in those equations that between other things gives both null points in any kind of alignment choosed and distortion levels.

The input variables need it to make the calculations are:

1- most outer groove record distance 2- most inner groove record distance and 3- tonearm effective length.

Does not exist null points for Löfgren B ( example. ) as a one and only solution: NO.

Null points depends directly not the kind of alignment but which outer/inner most groove distances we choosed as inputs in the equations/calculations. If we change these inputs null points will change it does not matters which kind of alignment we are using.

For years those two inputs were specified by the IEC and latter exist other standard DIN and exist JIS too ( any one of us can have our self standard too. ).
The IEC values are: 146.05/60.325 mm where the DIN: 146.3/57.5 mm

Through the calculations we achieve too the distortion levels that depends on where " are " the calculated null points. The calculations tell us the distortion levels in between the null points and outer both null points.

Overall the UNIDIN is higher in distortion level than Löfgren B in MF. example/picture.

Now, UNIDIN is it something special?: NO.

As I said everyone can have its " own solution " changing the inputs. If we use DIN against IEC standard the overall distortion level will be higher as is the uni-din.

So Löfgren or Baerwald has not an exclusive null points it only depends on the input choosed in the calculations ( there are several calculators over the net. ).

If we change the most inner groove distance input using IEC, this is that instead of 60.325 mm we take as input 54 mm then we have those null points in the picture as uni-din.

Normally when those two inputs are out of IEC standard overall distortion goes higher.

Can we heard at the inner grooves LPs a difference in better quality sound in uni-din than in Baerwald or Löfgren B?

If all those kind of alignments set ups were made accurately is almost imposible to hear. Why?, because the distortion level all over the recorded LP surface and at the inner grooves too is changing at each single groove with very low distortion values that can be really small as: 0.01% or maybe lower, IMHO no one can hear that distortion level changes even when that 0.01% goes to 0.2-0.3% we can't discern about.
Of course that if we use a poor cartridge tracker we can hear that in all kind of alignments.

I'm with the IEC standard ( I can change my mind in the future, who knows. ) and Baerwald or Löfgren B is ok if the alignment cartridge/tonearm is made it with absolute ACCURACY. This is the key word in " this alignment game ".
There is no perfect kind of alignment, in all exist trade-offs. Changing null points only define where we will have the diferent distortion levels through the recorded LP surface.

Why do you think the MINTLP protractor was and is so succesful? not only for its very low price but mainly for its accuracy do that the protractor is dedicated in specific not only to your tonearm but your TT too. Accurate.

So, any one of us can " invent " a new " black thread " for tonearm/cartridge alignment just changing one or those two inputs.

In the other side i would like to say that: LÖFGREN made maybe the greatness historycal audio contribution for you, me and everyone can for many years and many years to come follow enjoying our tonearm/cartridge combination listening in the right way the MUSIC we love.
My humble " hat off " for him.

Have fun!

silviajulieta's picture

That's exactly what Stevenson did it manipulating/changing the input to make that coincide one of the null point as the most inner groove distance and that's why overall Stevenson alignment has so higher distortion levels.

I can't understand why any one today can follow using Stevenson alignment when he can choose for better one as Baerwald or Löfgren B in favor of listening MUSIC.

Greetings.

silviajulieta's picture

Dear M./friends: I forgot, we can change too the effective length distance input to the calculations ( with/in the same tonearm we own. ).

If instead say 250 mm , that is the manufacturer spec ( example. ), we choose 253 mm the calculations will gives us a different offset angle, different overhang figure and diferent pivot to spindle distance.
Obviously that for we can change the EL input value we need that our tonearm headshell has slots with enough length to set up the cartridge to that new overhang and offset angle.

Normally if we go with a higher effective length distortions goes a little ( tiny ) lower and sometimes we could hear something diferent or maybe can't hear any change in the quality sound perfromance.

We can make anyb changes we want it. I prefer to follow Löfgren contribution and tonearm manufacturer effective length spec. Btw, if we know the tonearm effective length we don't need to know the pivot to spindle tonearm mounting distance because this comes after calculations for difference with the overhang calculated.

Regards.

X