Curved and Straight Tonearms

Genesis, I am using mine with a lightweight, non-FR, headshell, on which is mounted an Acutex LPM 320STR cartridge. I was prepared not to like this combination or to have a problem with bass response, at the very least, but I find that I do like it, and by this time I have been listening to it for nearly a year, off and on.  The bass has great definition within the musical envelope, with no hangover or spurious rumble. From what I have read, the FR headshells by themselves are quite heavy, and I assume therefore that they account for a significant fraction of the OEM effective mass of an FR64S.  I am also guessing that with my lightweight headshell, the effective mass is markedly reduced, although I haven't calculated it.  

Finally, the basis for Raul's criticism of these tonearms seems to be that they lack damping.  I have noted previously that in fact the pivot does seem to contain some viscous liquid that actually probably does provide a bit of damping. I infer this from the fact that at cold temperatures, the bearing becomes a bit stiff, overdamped in fact.  So, I think what might be going on is that Raul has a fact and an observation that he believes correlate. Fact: the tonearm has no damping (he assumes). Observation: He doesn't like this tonearm.  He is drawing a correlation between his listening experience and a principle of construction that may not be valid. We audiophiles commit this sin of attribution all the time. What is valid is his personal opinion that he does not like the FR tonearms, for whatever reason. I am fine with that. I wish he could stop by and hear mine.

genisis,
I couldn't agree more with your observations. I discovered how sensitive my FR64S was to the positioning of the Lateral Balance weight by accident. My Final Audio Parthenon TT uses a gunmetal arm board and has no adjustment - the TT has no compliant materials in its structure and relies on precision machining of all components. One of my aftermarket custom machined arm boards was out only by a few thou of an inch and the net result was higher than expected anti skate force required. Experimenting around quickly highlighted that when the few thou error in the arm board was corrected the Lateral Balance ended up smack bang back in the recommended neutral position described in the manual and the anti skate minimal. This also suggests that the bearings in my particular sample are very sensitive.

I currently own the following arms - Eminent Technology ET2, Naim Aro, Dynavector 501, Micro Seiki MA505iii (low effective mass) and 2 Fidelity Research FR64S'.  My preferred arms for ultimate performance are the ET2 and Naim Aro, but each arm has its plus' and minus' - the results can depend very much on cartridge matching, turntable and setup and this is the point often missed. I use the FR64S with an Ikeda Kiwame and Koetsu Black. My current reference is Naim Aro/Dynavector Karat Nova 13D or Eminent Technology ET2/whatever.

Lewm,
You are absolutely correct. Oil in the bearings will increase stiction and can even degrade the sound substantially at worst. I have no issue if Raul thinks that the FR64S is the worst arm he has ever heard in his system. However as you point out he cannot possibly ascribe the poor results he has experienced in his system to an attribute of the arm unless he has deconstructed the arm and run extensive lab tests trialling changes to the arm and measuring the results to isolate what each component and design element within the arm is contributing to any resonances generated by the cartridge on playback. Even then, the results can vary depending on cartridge, set up and arm board termination. Rauls' observations are only relevant within the context of the system in which has has heard the arm. He does not seem to grasp this concept and continues to make sweeping conclusions as you have alluded to.
With my Naim Aro the arm tube is purposely undamped, the designers intent is to transfer resonances as fast as possible to the unipivot bearing, where the bearing design and low centre of gravity from the underslung counterweight are designed to add mechanical damping by about 6-8db, from whence the residual is sunk to the arm board via mechanical grounding..     

Lewm, depending on cartridge compliance, you can easily match with different headshells. There are headshells from 8g all the way to 18g so you are pretty much covered. Yes both the 64s and 66s are amazing arms till today. I personally own over 25 arms (lost count) and that is still one of my top performer.

I have modern arms like the Reed, Dynavector, Graham Phantom 2 and Graham Elite and of course the SME V just to name a few and the FR is just as good or better when set up correctly.  

Setting the FR up properly is the key. In another thread the correct P to S distance for the 64s was said to be 231.5mm and best aligned with the Dennessen Protractor. I have several protractors for the arm. A Wally tracktor and the Dr Feikert and they do not sound close to what a dennessen does. I have mounted and set up many of the 64s for friends and clients and all of them are shocked what the arm is capable of. 

Finally since this thread is about straight vs curved arms, there is really no best but more different. All types have their pros and cons. Buy whatever that sounds good and works for you. That's why you need a turntable that has the capability to take more than one arm.