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 friends: I'm sure that many of us some way or the other are understanding in a best way the whole tonearm subjects on geometry/set-up.

One additional point that I want to address is one in reference on what Axel posted:

+++++ " There seems to be a MAJOR discrepancy here with some other expert Forum members that maintain that the pivot to centre-pin distance is NOT of the ULTIMATE importance .... " +++++

that is a mis-understood because the pivot to spindle distance is very important parameter in the right and precise cartridge/tonearm set-up.
No one can change this distance free-will with out alter all the other tonearm parameters.

If any one of you analize the calculations examples that I posted you can see that that distance always change and not because a free-will decision but because is a consequence of the use of te Baerwald/Lofgren/others equations.

It is a incorrect/wrong practice ttry to compensate errors somewhere changing free-will the pivot to spindle distance or changing free-will the overhang. We have to remember here that if we change the effective length the equation calculations give us a new overhang/offset angle parameters and a new pivot to spindle distance.
We can't change " free " any of those parameters with out alter the others and we must know eactly the new parameters values. Many people that goes that wrong practice forgot all these and forgot that exist a new and different offset angle too.

Of course that any one can do it if they have its own tonearm geometry equations and if not IMHO those almost free-will changes give them higher distortions results, no doubt about.

Like Dertonarm say: here it is not what anyone of us " think "/feel/hear it is pure geometry/mathematics/physics where the best we can do is FOLLOW IT to be nearer to the recording.

Regards and enjoy the music.
Raul.
I'm wrong, what we are doing is an additional arm wand of 2cm over 12", that's all.

Raul.
Dear All, I do agree with Raul on most of what he said in his last post.
However - let me put it in a few "axioms":

1) offset, overhang and effective length do relate to each other and CAN be CHANGED WITHOUT changing the PIVOT-BEARING DISTANCE. Offset, overhang and effective length do change when you align to a different arc-calculation (say - change from Baerwald to Loefgren).

2) If you change the pivot-bearing distance you change the WHOLE GEOMETRY of the given tonearm.

3) you get the very best results with the recommended pivot-bearing (= mounting distance as specified by the manufacturer, because the whole geometry of the given tonearm builds on that one parameter.

4) whether you choose Loefgren, Bauer, Baerwald, Stevenson or whatever calculation for the alignment of the stylus (and these calculations are onyl aiming at the position of the stylus - not at the position of the tonearm !!) is INDEPENDENT from the geometry of the tonearm itself. These alignments can all be done at the headshell alone without moving the base (and thus the pivot-bearing distance). And they should be done without moving the base because that way you can be sure that the basic geometry of your given tonearm is as specified by the manufacturer.

I think we must clearly put a line here between the geometry of the tonearm WITHOUT a cartridge. This is the basic geometry of teh tonearm itself.
Then there is teh geometry of the stylus in a given tonearm. This is step 2. Here we have the option to align to whatever calculation does fit our needs best (for instance more modern pressings with long run-out-grooves or pressings from the early 1960ies with the inner grooves running close to the label - these need different alignments - one rather Baerwald - one rather IEC). Here we lay the position of the 2 zero-error points and the maxima and minima derivation. This 2nd alignment does have variations in the offset, overhang and effective length (not much, but some) - but NOT in the pivot-bearing (mounting) distance.
Hi, just a little aside from behind the curtain as it were.

SME in their misguided wisdom using the "ICE-standard" (that strangely exists for LP manufacturing at al, BUT not cart ALIGNMENTS, correct me if I'm wrong ) for their alignment happen to use Baerwald, hallo!

Now Baerwald is what most everybody and his uncle is using these days... and is constantly being referred to in this here circle, very good.

The other item that might shine some light on this pivot to pin distance issue, and SME's disregard for such importance is: The SME V (in fact all 300 series) are based on a mounting hole to stylus tip distance of 9.52 mm or better 3/8". Therefore 233.15mm stylus-to-pivot distance, and a 23.6350 offset angle.

Most carts I've seen/worked with are ball-park, give or take 1/10 of a millimetre. This means that the post is move by about that amount to correct for overhang for that specific cart. A difference in VTF alone will change this distance by some 0.01 mm.
Nobody seems to take note here, that when a hole of some dimension about 32 mm is drilled in a plinth to take a fixed pin/pivot arm arrangement, that 1/10 mm or even less is simply within tolerance.
Unless this is done in a tool shop with a highly accurate machining set-up.
So whilst I DO agree with the importance of it all, I surely disagree to get complete anal about this. Reality of arm fitment is most probably a lot worse than <0.1 mm.

Now I feel so much better :-)
Greetings,
Axel
Dear Axel: Certainly the analog imperfect world " permit " that the people take decisions that are more oriented in " feelings " than in scientific care like the tonearm/cartridge set-up. Even those 0.1mm affect/provoke changes/distortions that are added at the whole audio system ones.

This kind of " behavior " unfortunately happen in every single link in the audio chain, sometimes by careless and sometimes by low know-how.

What is important to note is that many of those distortions are in our each one " hands " to make it lower if we take care on it not only in the whole system set-up but in the whole audio item system selection.

There are many many different subjects/factors that are "under " our each one control but even we don't know it.

Our each one audio learning curve is a " long road to home " journey where maybe the best way to help us is through an open attitude thinking that almost always exist a better " way " to make things to improve/grow-up.

I always try to think that the " best " is for coming.

Regards and enjoy the music.
Raul.