Tracking error distortion audibility


I recently unpacked my turntable from a couple of years of storage. It still sounds very good. Several times during playback of the first few albums I literally jumped from my chair to see which track was playing as it sounded so great. After a while I realized the "great" sound was always at one of the "null" points. They seem to occur at the approximately the proper place (about 125mm from spindle) and near the lead out groove. Questions:
Is this common? I have improved the resolution of my system since the table's been in storage but I don't remember hearing this before.
All others geometric sources of alignment error not defined by the null points (VTA, azimuth etc.) are essentially constant through out the arc correct? If so they should cancel out. I assume the remedy is a linear tracking arm but I am surprised at how obviously better the sound is at these two points.
Table - AR ES-1, Arm - Sumiko MMT, Cart. - Benz Glider, Pre - Audible Illusions, Speakers - Innersound electrostatic hybrid
Do linear arms really sound as good across the whole record as I hear at only the nulls with my set-up?
feathed
Dear Raul, the Dennes paper is very good indeed. Its a great classic since 2 decades. However - it too does only deal with the "2nd" geometry. Baerwald, Loefgren, bauer, Stevenson etc. - this is all about the geometry of the stylus in a given tonearm. Thats why the mounting distance is not taken into consideration at all - it is not needed in those calculations and it taken as any fixed parameter.
These calculations do not deal with a specific tonearm - they deal with the ALIGNMENT OF A STYLUS in an - already mounted to its individual geometry - given tonearm. All these papers do not deal with the basic geometry of the given tonearm.

Maybe we have a big missunderstanding here - I mean there is:

A) a basic geometry of the tonearm itself. This is an individual geometry of a given tonearm.
B) then there is the geometry of the stylus in a GIVEN (= its individual geometry already fullfilled) tonearm.

This - I would like to call it "individual" or "secondary" - geometry is kind of universal. It applies to ALL cartridges and have several options to calculate and align the tracking arc and its zero-error points and maxima and minima derivations from the arc.
Dear Dertonarm: Yes, I read and posted in your thread.

I understand that almost all of us are committed to set-up that stylus in the position where make less overall " harm ", that's why those white papers and " calculator " are so useful for everyone.

Regards and enjoy the music.
Raul.
Dear friends: Now that we are here and that some of us are " playing " with the information there are one or two subjects that can/could help to understand what is happening or what we are listening when ( example ) we buy a new protractor ( any ) and now with the new stylus set-up everything goes " better " ( many times does not goes better but we think it did. ).

With the " calculator " ( extremely easy and informative. ) and everytime you change your tonearm effective length you can calculate the new tracking distortion ( % ), maybe/could be that what you like is higher distortion.

This is one point the other one is that when you change the tonearm effective length through an overhang change you are changing too the tonearm/cartridge resonance frequency ( and change the tone in the sound reproduction. ) and is part of the " new " sound you are listening.

Maybe you can think that 2mm of cartridge movement is not important but it is due that you made that change where the cartridge weight makes more difference in that resonance frequency calculation: at the headshell/farest from the pivot tonearm.
Other factor that affects specially on the tonearm/cartridge tracking capacity is that moving mass change with the cartridge position.. I don't know if it is well say it but what I mean is that the tonearm and the tonearm pivot works more " comfortable " when " see " the cartridge weight/mass nearest to it.

Regards and enjoy the music.
Raul.
Dear Raul, a very interesting point.

You are right - the effective mass does indeed increase when you move the cartridge away from the pivot/bearing. The position of a given cartridge does have some influence on the resonance frequency. Whether it is enough to really contribute to the sound itself has to be explored. The effective moving mass of a pivot tonearm is also (sometimes very drastic...) affected by the weight of the cartridges body (Koetsu's stone bodies.....) and/or the weight of the headshell (lightweight Orsonic AV-11 vs. FR S/3 for instance - a difference of over 21 grams !!!).

Both these units do "sit" at the very end of the "balance gauge" and thus do contribute very strongly to the effective moving mass.

Very interesting point indeed!

This too is one of thereasons why the torsion resistance of a tonearm is so important - the further away the cartridge is, the higher its influence on the mechanic resonance behaviour of the tonearm.
Raul and Dertonarm,
Does either of you have an opinion on whether or not the advantages of lower theoretical distortion of a 12" arm outweigh the disadvantages of greater moving mass and potential for slight stylus misalignment being amplified more in a longer arm?

I'm curious about the differences between the 9" SME V and the new 12" SME V-12. This topic is discussed by Michael Fremer in the latest Stereophile review of the SME 20/12 and I'd like to read your opinions. Thanks. Peter