Where you position the tonearm ie alignment determines the arc of travel for your cartridge across the record.
Ideally alignment is based on at least two predetermined calculated null points any deviation from those points will introduce tracking distortions. Null location is derived from arm’s geometry and and will change accordingly if not based on the known alignment curves.
david
Yes, I can see that if one is aligning with a two null-point curve, that curve is specific to a particular tonearm. Or at least all of those type protractors I've seen are 'arm specfic. For a long time I used Wally Tractor's and had to have one for each 'arm. Superior to the Mint, imo.
With a protractor such as the popular SmarTractor that uses a single point (or the Uni-PRO which I have) the device is set to the correct P2S distance, then you adjust the cartridge to an overhang that puts the stylus in its 'right spot' and adjust for cantilever alignment. You pick a particular alignment (Baerwald, Loefgren, etc.) to do this.
So using that approach I figured I could align any tonearm to a particular alignment and presuming skill and the headshell allowing enough variance to adjust the cartridge, that the aligned cartridge matches the alignment I chose. For any 'arm. So finally here's my question: Would such an alignment be different if a tonearm specific two null-point protractor was used?
Sidebar: I'll note that for Dietrich's
Uni-PRO tractor he offers plug-in over-hang templates for specific tonearms as well as 'generic' templates for the standard set along with Uni-Din. These tonearm specific templates are not available for the SmarTractor.
He adds this note for his Uni-Pro:
This includes also all tonearms with an odd geometry. Tonearms NOT possible to align to any good results with any standard protractor.
Including tonearms like many vintage SAEC, Fidelity Research, Grace, Toho and many more, which do not follow Loefgren A / Baerwald nor Loefgren B nor Stevenson.
Maybe I'm answering my own question here (apologies). I assumed that if a tonearm physically allowed me align its cartridge to say Loefgren B, that tonearm accepted use of Loefgren B. Is that an incorrect assumption?