Comparison of sonic qualities of some tonearms

It is highly unusual for anyone to have two of exactly the same turntables

I never claimed to be ordinary! 😉

@mijostyn I have read most posts with interest, have I missed something.

Does a Tonearm have Sound as you are suggesting. 

I understand a Tonal  influence might be detectable?  

My own experiences always are dependent on the Cart' for sound.

Engineering, depending on the designs being produced, is a means to a consistent and predictable performance, not necessarily a betterment over other options.

I could happily live with a Kitchen Cabinet Door or Drawer that is not a Soft Close design. 

Correct me if I'm wrong, but do we not agree that tonearms do affect sound quality, and the point of this thread is how best to assess that? After all, if they do not, then it shall make no difference which one we buy or use.

As for how to check for differences, it seems the best chance would come from two tables of the same make and model, with the same cartridges of similar hours usage, feeding into the same electronics and speakers. The only difference would be the tonearm on each table. Listening performed blinded during the playing of the same LP on each table. Results in terms of preference would be valid for that cartridge only. That would be the science-based approach, and it is unlikely anyone would bother to do it.

The unscientific approach is one that, I think, still has some validity: a long term comparison and you see how much you are tempted to play music, and how long a session lasts. Lots of times I have liked a component, only to find myself choosing to do other things rather than listen to music. This is using the entire neurological path from eardrum to cortex as a meter that measures desire to listen to music. And that result, if it is to be trusted at all, can only be trusted by the owner of the brain concerned!

'Affect Sound Quality' , is quite different to 'how it sounds'.

Tonearm will impact on the sound the Cart' is able to produce, and certainly has the possibility to Influence Tone and dare I say Timbre. 

dogberry, A "scientific" approach is only possible if you have a calibrated instrument that does the listening itself.  Which of course is not going to fly.  In the end, we are stuck with subjective impressions.  This is why I said from the get-go that good judgements can best be made by a single listener in the context of his or her own home system.  After that, your construction of how to do the "unscientific" experiment works fine.  And, as I have said more than once, I have the wherewithal to do the experiment in my home.  Been doing it in fact for several years.  All I am left with are vague generalities, e.g., Triplanar is very good.  So is Fidelity Research FR64S in my hands, although some do not like it based on principles. Not going to mention the Viv Float.