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: That " calculator " give us many interesting " numbers ", example: the average distortion in a 12" tonerm is 0.3105% and in a 10" is 0.3815%, do you think can we hear the difference?

You can find out that tracking distortion/tracking error at any place/groove position in the LP and can compare between different tonearm lengths where you can ask: can/could I detect those distortion differences? are there real advantages on long tonearms?

This is only an example, there are more information on the whole subject including null points calculations.

I hope you can have fun with it.

Regards and enjoy the music.
Raul.
Dear Dertonarm: Please forget it what I ask you, I don't need that you corroborate nothing at all.

regards and enjoy the music.
Raul.
Dear Rauliruegas, all I did was displaying the geometrical facts. I don't know why you are so mad about this and why you have so many problems accepting these technical parameters which were and are used in analog playback in the past 6 decades.
Again - take the Graham and your comparism between Loefgren / Baerwald:

With the supplied Graham alignment tool you do adjust for either Baerwald or Loefgren. You do so with the detached armwand only and you do all adjustment at the headshell only. When the adjustment to either geometry is done,you fix the armwand to the - never moved... - armbase. So it is quite obvious, that the spindle-bearing pivot (=mounting) distance is not moved.

I think the big missunderstanding is that there are always 2 (TWO) geometrical calculations in tonearm playback.

a) the geometrical calculation of the pivot tonearm itself
b) the calculation of the arc with its 2 zero-error points.

b) can always bealtered by changing overhang and offset.
In doing so, we change the effective length and set the positons of the 2 zero-error points to different degrees on the arc and further apart or closer together to acommodate to LPs with longer run-out-grooves (IEC standard 1983) . The mounting distance remains the same.

Lets have a look at the tonearms you are using in your home system:
SAEC WE-8000, MAX-282, GST-801, AC-4400, IT-407, AR-1M - all these toenarms do not offer any possibility to change the mounting distance. Their bases are fixed. But you can nevertheless adjust tehir geometry to Loefgren/Baerwald or any other other arc-geometry - WITHOUT changing the mounting distance at all.
Same for Dynavector, EMT, Ortofon, Koetsu - the huge majority of tonearms does not feature a slide mounting base....... once you have drilled the mounting hole - thats it.
You can not change the mounting distance on these at all!
They are all fixed.
For good reason.
The sliding mount of the SME does lead into the erratic idea that mounting distance can be changed freely. This is a geometrical error.
Bob Graham used the SME slide mount because that mount was widely available and because it enables the user to adjust the mounting distance precisely to the manufacturers specs.
Dear Raul, you asked:

"Dear friends: Anyone of you can corroborate what I posted here:

www.ispexperts.com/BaerwaldLof...

Dertonarm: where can we corroborate what you posted? "

Where to corroborate my postings on this topic ?
In every decent (high-school) book about geometry........... and in the AES chronicles (but those too do demand some basic knowledge and understanding of geometry and interelations).

Regards and enjoy the music......
Dear Friends: I don't want to make this dialogue something " personal ", what Dertonarm or I think or argue about it does not matters, everything on the subject are already " say it " many years ago and the best we can do is to read on it.

Lofgren/Baerwald formulas were develped to obtain the overhang and offser angle in tonearm to " control " the tracking distortions.

Well, in those equations ( overhang/offset angle ) the parameters that they take in count are: effective length ( R or L in the equations. ) and the inner/outer groove radius. These equations have its " foundation " in those parameters not on the pivot to spindle distance.

Like I already say it:the subject is not what you say or what I say but what is wrong and what is correct.

All of us ( anyone ) can read here a very interesting analysis on the whole subject where you can find almost everything, please go to the link and there make click on Download and for the specific equations and notations ( R and L: effective length. ) go to page 30-32:

http://www.vinylengine.com/phpBB2/viewtopic.php?t=4854

I have to say that this white paper is really learning for anyone and along with the very first link ( calculator ) that I posted we can " play " to obtain amazing information on the tonearms we own and with the LP we own, like I say amazing. Now many of us can/could understand the whole subject and its implications.

Like I say in my first post in this subject a tonearm designer start/begin choosing the tonearm effective length for the design and not with the tonearm pivot to spindle distance that is only a consequence when we aply the Lofgren/Baerwald equations.

Regards and enjoy the music.
Raul.