What defines a good tonearm


I'm in the market for a very good tonearm as an upgrade from an SME 345 (309). Most of the tonearms I have used in the past are fixed bearing except for my Grace 704 unipivot. I dont have a problem with the "wobble" of a unipivot, and they seem the simplest to build, so if they are generally at least as good as a fixed pivot, why wouldnt everyone use a unipivot and put their efforts into developing easier vta, azimuth and vtf adjustments, and better arm materials. Or is there some inherent benefit to fixed pivot that makes them worth the extra effort to design and manufacture
manitunc
I repeat, there is no "best" arm. Attempting to judge sound quality by design parameters is impossible; what you are apparently searching for is a way to objectify a subjective judgement. If you like your present arm keep it until you hear something better or know why you are dissatisfied with it. Again your major premiss is wrong; there are not "certain design parameters that are attempted by all tonearms"; there is violent disagreement about pivot design, arm mass, straight line tracking vs pivoted and a myriad of other elements. There is a voluminous literature on all this that you can read at your leisure. The statement that if two things are different from each other then one must by definition be better is meaningless; the meaning of "better" will depend on external factors not defined. Ordinarily a million dollars is "better" than 10 gallons of water but not if you are lost in the desert.
Manitunc asked,
"My question is simply, which one comes closest to the ideal, mechanical and physical goal and why?"

A linear tracking arm, because it tracks the groove perfectly.
Bob
PHP143
If the first 100db suck, why continue?
I can only assume that you attended a school where the works of Aristotle still held pride of place.For most argument by definition is no longer valid.
I'm with Stan.

Having done this for 50+ years, I'm convinced there is no "best" tonearm. To think otherwise is quite short-sighted IMO.

I do, however, believe that some tonearms perform best with certain cartridges. One example is the Graham Phantom/Lyra Titan i combo. Absolutely killer. OTOH, in some tonearms the Titan i performs less than optimally due to the incredible energy it generates.

YMMV

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