What defines a good tonearm

Dear Hiho: Things IMHO are really more complex that what you posted or to that DO review.

I like to " see " things not only more in deep but where things happen: stylus tip/tracking grooves. As I said what almost all people see as " solved/fixed " unipivot unstabilities are really only at macro level but not at micro/nano levels where the unipivot simple has no time to recovery to take and execute the next cartridge " order " where a fixed bearing design IMHO is the best " slave " and best friend the cartridge is asking for.

+++++ " the positives outweighs the negatives. " +++++, well IMHO a fix bearing tonearm design has no discernable " negatives ".

Btw, thw whole subject is not only azymuth unstabilities but any single one around in all planes.

Statements like this with out any objective explanation is in the best case a misunderstood on the unipivot bearing type behavior and is something like if I say ( talking on motion cars. ): " the cycles will be the way to go and the ultimate design approach and stick by that ":

+++++ " unipivots will turn out to be the ultimate tonearm design approach and stick by that. " ++++

why is that? what makes the differences sole by the tonearm bearing type?, here we can say: " hey I like it that way " and if said it: yes, why? and probably the answer will be: " I don't know but I like unipivots ".

I think we have to be or to take a little more serious our hobby or at least try or intent to understand it even if we like a different approach. Please remember that what we like is no important when we are talking in objective terms.

I'm not against Mike or other unipivot advocates I'm questioning that: " I like it " with out foundation in objective terms in that specific tonearm bearing pivoted design, with no single explanation.
Seems to me that for some of you this unipivot subject is the " today fashion " just like the 12" long tonearms that gives no real advantages ( but disadvantages ) to the cartridge ridding: just think that the cartridge needs extremely fast response from the tonearm that depends on the pivot and from the stylus tip distance to the tonearm pivot. A 10" tonearm has a faster response over a 12" ( everything the same. ): don't you think?, remember that a tonearm must works in favor of cartridge grooves ride as better and faster respond to cartridge needs as better that tonearm.

I'm not questioning that a cartridge/unipivot combination likes any one of us over a fixed bearing cartridge combination because this quality performance level depends on many factors where the pivot tonearm bearing type is one of those factors.

I don't know the whole method/process that Mike, you or any other person have to detect in a precise way distortions and to discern from where that distortion comes but I can say for sure that if we don't have that method/process to be aware about all what we have to say on the pivot subject has almost no validity other that " I don't know but I like it ".
I hope some of you have a better answer than that.

Anyway, I think that from my part was enough and in the other side the thread helps to know what each one of us " think " on the issue.

Regards and enjoy the music,
raul.

As with most 'purist' audio concepts like 'valves vs SS'....'belt-drive vs DD vs rim-drive'.....'horns vs panels vs dynamic speakers'.....there is no one 'correct' solution or answer.
Rather, it is in the execution of a particular solution whereby a particular design may excel over another?
I have unipivots ( or dual pivots) like the Hadcock GH228, Phantom II and Copperhead.
I also have double gimbal bearing arms like the DaVinci 12" Ref Grandezza, Fidelity Research FR-64s and FR-66s and Micro Seki MA-505s and I have a double knife-edge bearing arm....SAEC WE-308.
You would think that if there were 'differences' inherent in the design philosophies of these arms alone...... they would be audible in side by side comparisons?
Apart from the Phantom II not liking high-compliance MM cartridges and the Hadcock not liking high-energy cartridges like the Titani, I find the differences between the various arms to be those of execution and quality.
There are far greater differences between cartridges than those between differently-principled arms IMHO.

Hiho, are you beginning to see the religious nature of all of this? ;-)

So much misinformation here.

A properly designed unpivot arm does not rock due to stylus tracking simply because the design has the stylus aligned with the pivot point; there is no torsional leverage and the only degrees of freedom from the stylus are the planes in the vertical and horizontal, which is what ANY arm has to have. There is no torsional "rocking" due to stylus motion in the two planes of a stereo recording going and what little of very low frequency may be provided from record warps and non-centered hole are effectively damped and remian unheard.

This is a very intelligent, reasoned discussion. It seems we all agree on certain major points as regards the advantages and disadvantages of unipivot designs vs fixed bearing designs. And I like that Hiho mentioned the issue of azimuth adjustment (AA) when it takes place upstream from the headshell (cannot avoid also altering both VTA and the angle in space between cantilever and LP surface). But that would be the same for both basic types of pivoted tonearm. As far as I know, the only "modern" tonearm that permits AA at the headshell itself is the Reed, when ordered with the optional AA headshell. I hope you unipivot guys will agree also that it is the cartridge that needs to follow the groove and that Ralph is quite correct to say that if the tonearm per se were to respond to the groove undulations, there would be no music. What lies in between those two extremes is probably what actually happens with most unipivots. Still, I have to explain the ethereal quality of the Talea that I heard locally. It made me want one. Obviously, the Talea "works". In thinking about what I heard from it, I came to the tentative conclusion that in part I was responding to highly euphonic "imperfections" that I have heard before with unipivots in my own system. I think this is what Mike was trying to get at; there is a certain sense of freedom (still not a perfect word for it) associated with unipivots that is very beguiling. And that's perfectly OK in my book.