How important is the tonearm?

01-27-11: Dan_ed
The job of the tonearm is to hold the cartridge in the groove with the grip and determination of The Incredible Hulk while maintaining the finesse of Tinkerbell.

could you explain what characteristic would allow one tonearm to inherently "hold the cartridge" better than another tonearm? i would prefer an answer with specificity over a generalized "it is widely known" type of response. i ask this because as long as the tonearm is rigid (and all tonearms of which i am aware has this characteristic) then i am having difficulty understanding what the difference really is.

what does seem to me to be of importance is the effective mass of the tonearm, but the signiificance of this must be evaluated based on the compliance of the cartridge that is to be mounted on the tonearm. here, i can see a consideration that has importance. but this is a matter of effective mass and not of the specific brand of tonearm. the reason why you care about the effective mass is because the compliance of the cartridge is a measure of the spring properties of the cartridge. when the effective mass of the tonearm is not properly matched with the compliance of the cartridge you can get resonances at low frequencies that can make the cartridge become unstable in the groove. but this analysis would suggest that what you really care about in a "good arm" is one whose effective mass is appropriate for the compliance of the cartridge. so the real question that i am referring to in my earlier comments is, what other characteristics about the tonearm have concrete significance? it is hard for me to grasp assertions that a $10,000 tonearm is better than a $100 tonearm simply because the former costs 100 times more than the latter.

01-30-11: Davide256
2# quality of arm does affect the ability to trace microtransients and not distort peak transients. A mediocre arm reduces that sense of "air" in a recording and direct to discs will make you want to shoot the arm and put it out of its misery. The arm basically rings like a bell at unpredictable frequencies and amplitudes in sympathy to the stylus vibration.

Better arms have fairly sophisticated schemes of minimizing resonances. Beware of any tonearm with dangling parts, thats a resonance PITA. An excellent tonearm should have a machined approach like jewel movement swiss watches.

i see. this sounds like a pretty reasonable explanation. i have a triplanar tonearm and one thing that i have noticed is that the tonearm seems very dead in the sense that if you tap the tonearm the material from which the tonearm is made deadens vibrations. an impulse tap contains a fairly wide range of frequncies so that test would suggest to me that the triplanar tonearm is not particularly prone to coupling longitudinal resonances along the wand.

01-31-11: Dan_ed
Paperw8, most any tonearm is a complex system in itself. Sorry, no easy answers.

you should always question your own assumptions to make sure that you actually know what you are talking about. if you just accept the "it's inscrutable" line, then you are like so many of the "audiophiles" who spout commentaries on this site but who substantively don't know what they are talking about.

i am not suggesting that all of this subject matter is trivial, but my feeling is that i at least try to understand it. "trust your ears" is just not sufficient; if you can't gain some understanding of a process for purchase decision-making you are just throwing your money away. think about it, with all the equipment out there and all of the "synergy" issues that are about, there is virtually an infinite number of different combinations of equipment that one can try. even a turntable system involves a daunting array of choices between the variety of cartridges, tonearms, turntables, tonearm cables and phono stages - and all of that is before you even get to the preamplifier! you have to have some way to cut down the possibilities.