How to measure tonearm effective mass

Lewm

I was just being facetious ... You ask a simple question and get very complicated answers but you are right it is a very good question...

Hey Chuck. Are you THE Chuck, formerly of Northern Virginia, to whom I spoke at RMAF?

The confounding reports of apparent tonearm/cartridge mismatches that sound great have me thinking about the quality of the data for compliance and tonearm effective mass that we start with. Also, for some of the newer/newest tonearms, there are NO data coming from the maker. To wit, I asked a dealer about the effective mass of the Talea. Turns out an exact number is not available.

Of course also, Raul and others have correctly (probably) pointed out that the compliance/mass issue is not at all the sole determinant of a good tonearm/cartridge marriage. I suspect that is a very important truth.

Dear Lewm: +++++ " have correctly (probably) pointed out that the compliance/mass issue is not at all the sole determinant of a good tonearm/cartridge marriage. I suspect that is a very important truth. " +++++

why you have doubts about with so many testimonies not only on that MM thread but on other threads and even on proffesional reviews like that one that I pointed out in more than one ocassion review on Audio magazyne (1984) reviewed Ortofon MC 2000 cartridge. Well, maybe because you are " technical " oriented and like to know in precise way the why's, I would like to know it too.

Now, some way or the other we have to trust in the tonearm/cartridge manufacturer specs, yes maybe sometimes could be some errors but I think normaly are trusty numbers.

In other side, what I think we need is some one that take the task to " design " a mathematical/computer model that take in count any single factor/parameter/subject that has influence in the cartridge quality performance level and that could give us an " idea " of what to expect with a cartridge under " some/any " circumstances " where cartridge is surrounded.
Who say I take it?

Regards and enjoy the music,
Raul.

Lew, All I can contribute on this subject is the result of modifying a linear arm to allow micro adjustments to effective vertical mass across a wide range of adjustment. This set-up separates observations related to changing effective mass from observations related to changes in wand composition or length. The effects are remarkable. So far in limited experience with a few cartridges, small changes in effective mass have more impact than VTF on taming subtle tracking problems and improving LF performance. The granularity and wide range of adjustment necessary to optimize each cartridge, suggest that the broad categories of light, medium, and heavy arms may be too coarse to consumate perfect marriage between arm and cartridge-- unless achieved by guess and by gosh.

Funny that only one pivoted tonearm I can think of actually has capacity to alter its effective mass, and that is the MA707 or the CF1 (or both) made by Micro Seiki. They used the simple device of a weight that slides fore and aft on the arm tube. You'd think that idea would have been widely adopted. Maybe they had a patent.