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
Dear Hiho: You are right, the majority are dual points. The first two points design I know was the one from Audiocraft 3300/4400 from what born the Graham.

All what " surrounded " a cartridge playback is so imperfect that an unipivot ( true one. ) design can't hyandle. We have to think on the forces around LP off center holes along non flat records along what the stylus tip has to negociate on the grooves. A unipivot design is at mercy of all those imperfections along the tracking tip forces that due to its inherent unstability preclude as a " best " bearing choice. This not means it can't works because we have several examples that said it works but the penalties are additional distortions that a fixed bearing ones does not have because that regards.

The cartridge needs at least in the tonearm: stability, dead stability because it is surrounded for to many unstabilities elsewhere.

What like we at home?, IMHO it depends on what kind and level of distortions we accept, which kind of trade-offs we are willing to accept.
Of course that some way or the other we have to have an objective method/process to be aware of different kind of distortions and different level of those distortions.
Many of us are not aware of those distortions and like what we are hearing with out note that what we are hearing is full of distortions.

As I said I prefer a fixed bearing pivoted tonearm against an unipivot but this is me.

My take is that whatever happen between the stylus tip, grooves and record and recording imperfections the tonearm task is to stay steady and neutral to those " movements " adding nothing that put additional " problems " to the cartridge very hard task.

Lewm, lowering by design thgose unipivots issues does not menas disappeared or that has no influence, its means only that the problems are only a little better under " control " but its influence is always there.

The fixed bearing design is perfect?, certainly not nothing is perfect but is more cartridge's friendly and this fact makes an overall difference everything the same.

Regards and enjoy the music,
Raul.

I meant to say "it's fun for me to think about these things and I DON'T have dog in this fight." I apologize for all the bad spellings and syntax.

______
Dear Hiho, I was looking for your dog. Thanks. But be careful using the word "syntax", or you will conjure up Syntax himself, that man of mystery.
BEST Tonearm can only be.. when mated to "the" accomodating cartridge, mounted to "best" symbiotic table, matched to "correct" receptive Preamp, and owned "by" narcissistic personality type. The rest of us will continue the search....