Cartridge Compliance Conversion

Empirical testing by Audio Asylum correspondent Garth using a Schröder arm with a verified effective mass showed that the DL-103's compliance is likely 10-12 cu if it were measured by the standard method used by most cartridge manufacturers. There's lots of real world experience demonstrating that the 103 works well in medium mass arms such as Regas that, using the familiar resonance frequency formula, should be gross mismatches.

Robdoorack:

Which version of the DL-103 was tested? I was interested in the DL-130D. Also, is there a way to measure empirically the effictive mass of a tonearm, or must we trust the published specfications? For example, after a tonearm wire upgrade, it seems reasonable to think that the effective mass would change, and it would be nice to verify it. I just got finished reading the VDH treatise and got interested in this formula from a theoretical interest, but I appreciate your candor about whether or not it is all that useful.

-Marc

Rewires may somehow affect the effective mass of a tonearm, but what about the heavier counterweights? The original counterweight on the Rega RB300 is 95 grams and the Clearudio Turboweight for example is 135 grams... How does this affect the effective arm mass? Is it safe to divide 135 by 95 (equals 1.42) and multiply this with the original effective mass, i.e. 12 grams X 1.42 = 17 grams for the Rega? Or is it better to calculate the extra 40 grams as a percentage of the total mass of the arm?
Is there a proper definition of the term "arm effective mass" somewhere? I am quoting a frequently used definition:

Effective tonearm mass: The total mass of a tonearm's moving parts, and where along the tonearm that mass is distributed. Mass near the pivot point only slightly increases a tonearm's effective mass, but the same amount of mass near the tonearm's cartridge end greatly increases the effective mass.

If this is correct, shouldn't the counterweight added to the arm's mass since it is a moving part?
Regards,
Panayiotis