Multiple arms, multiple cartridges and geometry?

I have read the debates regarding the benefits of different tonearm geometries......Lofgren A and B, Baerwald, Stevenson etc....and I appreciate the benefits of choosing where, on the vinyl record, one wishes to have the least spread of distortion.
I also have read where certain arms seem to perform better with one or other of these geometries?

I have two turntables with three different arms on each one and I have a total of over twenty five different cartridges.
Four of those arms have removable headshells and twenty of my cartridges are mounted on their own headshells ready for installation into any of those four tonearms.
How then.......can I have different geometries for each arm if I don't wish to re-align a cartridge within its headshell depending on the arm in which its installed?
Surely......I must select a single geometry for all my arms so that the cartridges fixed to their headshells....are truly interchangeable?
Dear Halcro: To do that, fully interchangeable, you need that those tonearms share same effective length and if not then you need to " force " all tonearms on the choosed efective length.

Remember that's the effective length where those tonearm geometries moves around.
All those calculations takes as main parameter the effective length and then through its equations achieve the overhang and off-set angle and by difference the spindle to bearing center distance.

I hope this can help.

Regards and enjoy the music,
You have obviously set out to drive yourself nuts. Oh, wait; we are audiophiles and therefore already nuts by definition. Sorry, my bad.
Dear Raul,
Oh mean that when I set up a cartridge on one arm with, say.....Baerwald doesn't mean that it will be correct if I change to another arm with a different pivot to spindle distance and overhang?
I somehow feared this might be the case.....and I can easily check it......but damn!!!! Stanwal then says.....I am forever going to drive myself mad by changing and checking geometry at every change of tonearm and cartridge?
Oh boy......what a disaster!!?
Dear Henry, You need, it seems, to start a new. I hope that
you own no more then 400 Lp's so you can rearange them according to the distance of the outer groove to the spindle. Assuming 3 geometries you will have then 3 kinds
of LP's collections which is 3x more then we, the other, have because we own just one collection. Then you should mark all your tonearms according to the new ranking or geometry while the same should be done with the carts/headshell combos. This way you will have 3 kinds of every kind while thanks to the markings no confusion
will ever (more) occur.

Just go digital and be worry free or at least trade yours for a different set! :-)
" mean that when I set up a cartridge on one arm with, say.....Baerwald doesn't mean that it will be correct if I change to another arm with a different pivot to spindle distance and overhang?"

Yes; it will not be correct. But your tonearms are vintage Japanese types. Many or most of those were designed with Stevenson geometry in mind or with some idiosyncratic geometry unique to that tonearm (e.g., SAEC 308SX). You can use Baerwald alignment for some of them (not SAEC 308SX), if you must, but the cartridge will end up twisted with respect to the long axis of the headshell. My experiments with doing that did not sound good. But no matter what geometry you use, a given alignment of the cartridge will work in two different tonearms only if they have the exact same P2S distance, effective length, headshell offset angle.
How about using a standard alignment template, whichever one might be best for your table, similar to the user printable one that Linn has provided for the Axis specifically, and just applying it as needed?

That has always worked for me with the Linn Axis in terms of getting hard to fault sound quality, ie faultless tracking, good dynamics, quiet background, and no sibilance, which are usually 4 very good indicators that things are working well.

I have never swapped arms, but if the template could not work, that would tell me the arm is not a match to the table.

Why make these things more complicated than need be?
Dear Mapman,
Your alignment template works for your tonearm. It's specific to the Linn tonearm. I cannot imagine how to design a "standard template" that is turntable specific. The turntable does not give a rat's butt what tonearm is mounted on it, so long as the tonearm will fit on the mounting platform. I don't think off the top of my head that there is any way to escape the necessity of re-aligning each cartridge for each tonearm, unless the two tonearms have identical length parameters and headshell offset angle.

But, Halcro, I just remembered that you do use outboard arm pods that can be moved around freely wrt your TT101. This gives you more degrees of freedom wrt P2S distance, but won't completely obviate the need for tonearm-specific alignment.
Dear Nikola,
Que??.........'re right about my ability to 'massage' the spindle to pivot distances for all my arms.
I'm thinking......and I may be wrong (need to check the Vinyl Engine formula)....... Whether I can adjust the P to S dimension of all the arms to have a uniform 'overhang' dimension?
Will that allow for a 'common' interchangeability?
Dear Halcro: I think that I don't explain to good or that you did not understand what I posted, here again:

first I don't know why you want differnt geometry alignment for each tonearm ( Baerwald, Stevenson, L¨fgren or what ever. ).
If you need full interchangeability you must choose one geometry alignment for all tonearms.

When we choose in that way, example: Löfgren B, even if the tonearm effective length is different from each tonearm we can force the calculations to one effective length for all the tonearms, in this way the overhang and offset angle will be the same to all tonearms and with full interchangeability.

Subject is to choose the " right " effective lenght value that permit the cartridge overhang set up for all tonearms. So, if for example you choose: 260mm that means that all tonearms must be mounted to conform that effective length minus the calculated overhang.

This could do it or not depending how large are the true tonearm efective lenght differences between each of the four tonearms. So, not always is possible to have that full interchangeability.

Regards and enjoy the music,
Henry - for the arms you use that have detachable headshells, surely if you use a headshell that has slots, hence the ability to alter the overhang and alignment, then you can set each cartridge up and the only changeover issues would be tracking weight and VTA. I use to build easy VTA adjusters by tapping a metal block and using a fine thread screw to put under the arm lift. If you recorded the optimum for each cartridge/arm then it becomes easy to adjust.
Failing all this - buy 2 more TT's & enough arms and you can at least get 24 of your cartridges running simultaneously.
and the only changeover issues would be tracking weight and VTA.
That's what I thought and the principle I have been operating under?
However.....I fear that is not the case?
The effective lengths and overhangs being different for all my arms......means the arm geometry is not easily transferable?

I agree that I need to accept the same geometrical alignment for all the arms I wish to use with detachable headshells......say Baerwald?
I can appreciate that I can adjust the P to S distance of each arm so that the 'Overhang' can be the same.......but I don't see how I can adjust the effective lengths between 222mm, 230mm or 295mm to be the same? :-(

Can you possible explain a bit more thoroughly?

Dear Henry, Sorry, I overrated my Sliwowitz capacity. My
consideration was: the distance between the lead out
groove to the spindle differ by the most LP's. Depending from this distance Stivenson and Bearwald will give different inner 'O' points which means that one will be
more optimal than the other in (co) relation to the LP
you intend to play. You can estimate the distance or measure and then decide which tonearm (aka geometry) to use. Ie the geometry is primary about the records and only
'indirectly' about the tonearms.

Halcro, thinking you may be able to work this backwards. ie allign MA505 to your chosen common allignment. Remove the headshell and put it on one of your other tonearms. Move P2S for that arm so that it follows the arc that the MA505 used then record the new P2S for future referance. Just a thought but not sure if this would work due to the differences of offset and overhang between the arms you use.
Nandric nailed it.

Get to work, and you might as well enter the S2IG (spindle-to-inner groove) dimension in a searchable database while you're at it.
Hi Halcro,
you said:
How then.......can I have different geometries for each arm if I don't wish to re-align a cartridge within its headshell depending on the arm in which its installed?
Surely......I must select a single geometry for all my arms so that the cartridges fixed to their headshells....are truly interchangeable?

I see you are still pursuing this quest. Previously I posted regarding a similar issue you asked about
...It looks to me that swapping headshells between arms would require them to be set up initially with oneheadshell/ cartridge combination which remained set once the first arm was done, and which was then used to set the remaining arms with adjustment achieved at the bases of the others, assuming they were different arms.

The alignment chosen would have to also be the same for each set up, irrespective of the arm design, but the arms could be different lengths. Then any cartridge/ headshellcombination could be set up to suit these alignments without moving the bases. This would depend on the headshells having slots, though the initial headshell could have holes as long as the arm used was designed to the chosen alignment.

So headshell swopping only works with arms of the same alignment. where one cartridge is used initially with one arm then that cartridge is used to set the mounting distance for the rest.

You could also set for Lofgren B, using the same headshell/cartridge by setting an arm closer to the spindle, thus increasing overhang by around half a millimetre (depending on effective length), as the cartridge offset remains the same using an adjustable base.

For other non LofgrenA arms you would have to know the offset angle and whether you could achieve a suitable alignment with a cartridge already mounted correctly for LofgrenA by adjusting the mounting distance only.

Have fun...

Yes Ecir and John,
I'd forgotten your earlier response on this subject John.......but reverse engineering seems to be the way to go?
I will try it and see if it works on all my arms with all my cartridges?
Thanks...and keep tuned :^)

My opinion is that if you care about really precise alignment according to any single one of the standard geometries (you pick), and given that your tonearms all have different recommended P2S, effective length, headshell offset (which may or may not be true, but from your system photos it looks to be true), this cannot be done. "This" is defined as mounting each cartridge in a headshell such that any headshell/cartridge can be used with any of your tonearms without further tonearm-specific adjustment to achieve proper alignment.
OK........have just spent the day checking my arms and cartridges :-(
Who said that "Analogue starts with anal"?
Apart from one of my ZYX Universe cartridges mounted in the DaVinci 12" Grandezza and one of my Empire 4000D/III Gold cartridges which is fixed into the Continuum Copperhead tonearm.........all my other cartridges are fixed into removable headshells which have been aligned using Dertonarm's UNI-Protractor with the Fidelity Research FR-66s template and arm mounted at 295mm S to P.

I inserted some random headshell/cartridge combinations into the Micro Seiki MA-505s mounted at the recommended 222mm S to P distance and checked the alignment against the UNI-Protractor with the MA-505 template inserted.
The alignments were almost perfect......but a correction to 223mm S to P distance.....DID make them perfect :-)

I next inserted some random headshell/cartridge combinations into the FR-64s tonearm mounted at the recommended 230mm S to P distance......and lo and behold.......perfect alignment :-)

Moving onto the SAEC-308N with a recommended 235mm S to P distance......I could not make any headshell/cartridge combination align with the correct point?! At the furthest headshell slot.....the stylus point was always 3-4mm too short. Four different headshells were tried with the same result?!
I remember this happening with my Grace 940G tonearm as well....with only one headshell able to stretch to the correct distance?
I then remember what Daniel had written to me about the 235mm distance when he sent me TWO templates for the at the 235mm S to P distance...and another at 225mm S to P??
It is indeed, but it results in a rather "sub-optimal" overhang of 5 mm only.
The resulting tangential curve is catastrophe.
The overhang has to be prolonged.
My template (at 225mm) results in effective length 251.1 mm.
So I moved the armpod to give the alternate 225mm S to P dimension......but of course all my headshell/cartridge combinations did not work!?
The off-set angles and overhangs were totally wrong :-(
They required massive twisting of the cartridges in the headshells to be aligned correctly and only the Yamamoto wooden HS-1AS and Micro Seiki headshells allowed such extreme twisting?
So I selected about 4 or 5 MM cartridges in these headshells...and aligned them according to the UNI-Protractor with the 225mm template.

Ahhhh........the sound....the joy....the bliss!!

So the net result is this:-
I have two tonearms (the Copperhead and DaVinci) without interchangeable headshells.
I have three tonearms with interchangeable headshells which accept any of 20 of my cartridges pre-mounted in their individual headshells...with correct geometry.
I have one tonearm with interchangeable headshell capability (MA-505s).....which has five dedicated headshell/cartridge options ready for instant insertion.

I'm like a pig in mud.....only cleaner.
SO the big does it all sound? How do you choose which setup to use when playing a record? Was it all worth it?
Dear Halcro: Why not align all the removable headshell tonearm designs at 225-227mm according Löfgren A or B calculations?

You could try that: same tonearm effective length, this means same overhang and same offset angle with different tonearm spindle to tonearm bearing mount distance.

Regards and enjoy the music,
Great efforts Halcro and I appreciate your sharing the experience with us. But I
can't fathom the sheer number of choices you have each time you sit down to
relax and listen to music. I sometimes have trouble just deciding which LP to
pull out. How do you do it?
Dear Raul,
Why not align all tonearm designs at 225-227mm?
It ain't a pretty sight huh??.....and most arms should sound their best at their Manufacturers recommended specifications?
But apart from all that......I would then not be able to use cartridges with fixed headshells such as the FR-7f and the Technics EPC100Mk3?

Good questions Mapman and Peter......
In one way I agree with both of you. There really are too many choices BEFORE I even choose a record to play?!

On the other hand......for 30 years.....I listened to one turntable with one arm and one cartridge (although that cartridge might change every 2-3 years?).
And was very enjoyable.
But each time a new cartridge was inserted.....a different perspective was given to all my cherished records. Sometimes....this different perspective seemed a step backwards....or at least....gave less satisfaction?
Only when a new cartridge gave a keener insight into the listening experience.....did it stay for the course.
But the sheer fact that every cartridge DID sound differently should have raised some important there a 'correct' sound to a cartridge? ABSOLUTE sound?
The answer of we all NO.
That is why we all have different systems with different sounds....and I won't venture into the preferences for valves vs solid state, belt-drive vs DD, MCs vs MM, planars vs horns vs dynamic vs sealed vs ported??

If every cartridge offers a different perspective....and every arm and turntable likewise......aren't there some benefits to being able to instantly sample those perspectives on a daily basis?

And that's precisely what I do!
Sometimes I'm entranced with the sound of a particular cartridge on a particular arm I'm using....and will listen to records for day after day until suddenly.........I will hear something on a track that triggers a desire for a 'different' perspective?
This may entail the 'radical' shift to my other turntable with a totally different arm and cartridge 'type'?

Most audiophiles don't use 'tone-controls' or equalisers and need to change a component or cable to effect a change in sound to their set-up?
Imagine being able to do that every hour of the day...every day of the week? choices are now vast compared to most audiophiles....but the increase in my knowledge and listening experiences allows for a greater appreciation of the variations and diversities which make up this intriguing hobby?
Anyway....that's my story and I'm sticking to it?! :-)

Henry, this reminds me of an experience with the Cello Pallette equaliser, where in the hands on a record producer it was a very good tool for poorly mixed records and did give more insight and enjoyment from the music.
I would have thought that if you find the optimum arm for each cartridge, then just switch those combinations - much less stress and dare I say it a move towards minimalism.
Dear Henry, So far as I can overlook our members only Thuchan and Raul will really understand your effort. The rest of us can only repeat after Hawking ('History of time'): 'to many variables'.

Addition. With so many variables one can forget about the
constants. Why do you assume 'constant records' while the distance between the modulated inner groove and the spindle is variable? What is the sense of '0' point at an position on the record with no modulated grooves? I thought that
the different tonearm geometries are about those 'o' points. Ie we are supposed to have the choice among them. That is to say where on the record we want them.
My idea is to have Stivenson and Bearwald and then select
one of them by each LP depending from the mentioned distance.


No worse I suppose then me having to pick a room to listen in. I had in wall speaker wires run to 5 rooms and my deck when my house was built. Instead of swapping carts, I have to run downstairs and select the room on the speaker switch. I suppose we all appear to be nuts to most.

Now I also have two systems in two rooms, a table radio in a third, and a tablet device and two laptops connected to my music server. My wife goes nuts trying to figure out where the music is coming from at any given time and usually how to turn it down!
Dear Nikola,
Thuchan and Raul will really understand your effort.
Now that you've pointed it out........I realise how in the minority I really am?!

But what is this....changing the geometry to match the record??!
When you are telling me that this is what YOU do.......then I might think about it?
On the other I won't :-)

But you once wrote a very telling post which I remember very said:-
If there are two 'null' points on every side of a vinyl record where the cartridge is in perfect geometrical alignment.......why don't we jump up and shout "Eureka" when we hear these two magical moments on each side?

And the answer is.............

Kind Regards
Dear Mapman,

Shouldn't the letter 'p' in your a 'd' :-)
Dear Halcro: I see The Reason but my question is: do you already try to set up your removable headshell tonearm designs at 225-227mm on Löfgren B geometry?

Regards and enjoy the music,
Dear Henry, My father hated two kinds of the human kind:
the politian and the phylosopher. The reason: 'while everybody else try to solve some problem those two are only causing problems'. The phylosopher even for the sake
of argument (aka invented problems) for which they are willing to kill each other. They also invented 'the idea of the idea'. Well those '0' points are in a sense phylosophical points. We need to have the(firm) idea that those points are in the right place. Otherwise we can't sleep in a healty way. The trouble is that there are different
geometries with different '0' points while we are not sure
which are the right one. BTW my father killed himself when
his son enrolled the faculty of phylosophy...I heard about Freud much latter.
Halcro - the Eureka moments are gone in a blink of an eyelid. Just enjoy the fact that you know they are there.
I think Mapman has a potentially lucrative business - "My wife goes nuts trying to figure out where the music is coming from at any given time and usually how to turn it down" - there is a $$$value added proposition in there somewhere.
Dear Halcro You ask for full interchangeability between your removable headshell tonearms you own noty that " looking good ".

Do you already tested to mount your three tonearms at 225-227mm with Löfgren A/B geometry set up?

Regrads and enjoy the music,