A Copernican View of the Turntable System

Dear Nandric, In regards to your post of 08-10-11, I think that the maker of the tonearm, by selecting the offset angle of the headshell and by selecting an upper and lower limit for effective length (the margins for this being equal to the length of the parallel slots in the headshell that permit fore and aft movement of the cartridge), has pari passu selected for us an optimal geometry. We (the end user) are largely denied the luxury of deciding for ourselves where we want our null points with respect to innermost vs outermost grooves. Unless of course one wants to put up with distortions created by forcing an inappropriate geometry to be made to "work". In my experience of N=1 it is best to go with the tonearm designer.

Dear Lew, The math was alas my worst subject at school
but I thougt in terms of 'variables' and 'constants'in this context. I know that the term 'variable' has no sense in the math (thanks to Frege)but we are used, so to speak,
to use those terms. Well if we are free to choose the 'zero points' as we like or depending where we want the the least distortion than this means to me something that is 'variable'. So consequently there must be 'something' which should be constant. So I thought that
this must be the tonearm 'on its own'. I am sorry for my terminology but that is what I thought. From your statements I 'see' or deduce that we have no choice at all in the sense mentioned. Ie the designer of the tonearm in casu predeterminated our 'choice' in advance , so to speak. Ergo we have no 'free choice' at all? What an hobby!

Regards,

Dear Nandric, dear Lewm, I am happy to talk in length about tangential curve and tonearm(s) "on their own", but we should do this in a separate thread.
Because - IMHO - this will soon leave Copernican view and separate arm pods ....
So much for now - no, you can't choose your zero points freely (at least not on a 12" record ...) - not if you want any decent positive results from tracking the signal in the groove.
Cheers,
D.

Dear DT, It's relevant to this thread only in that it points out the critical nature of tonearm alignment for those who wish to use outboard arm pods that are free to move about in relation to the tt spindle. (I will now don my armor plating.)

Lewm: I hope that armor plating doesn't shield you from the truth, because here's some coming at you.

I aligned my cart with a Mint protractor around a week ago. Your post and my previous concerns prompted me to check alignment just now. It's dead on. I used a 10x loupe. I must say I'm slightly surprised by this, but in my mind this is pretty conclusive as to the stability of the Copernican system.