found this. Is it about right?
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The only way to accurately measure system resonance is with a calibrated low frequency test record and a chart recorder, or other sophisticated test equipment. Since most of us do not possess this capability, it is wise to do some preliminary homework in assessing the compatibility of any potential arm/cartridge combination. There are a few general "rules of thumb" that we need to consider:"
* A tonearm whose effective mass is rated at 10 grams or below is considered low mass (e.g. early SME’s, Grace 747 etc.). A tonearm whose effective mass is rated between 11 and 25 grams is considered moderate mass (e.g. SME 309, IV, IV-Vi, V, Triplanar, Graham). Arms above 25 grams of mass are high mass in nature (Eminent Technology, Dynavector).
* A phono cartridge whose compliance is rated at 12 x l0ˉ6 or below, is considered low compliance. A cartridge whose compliance is rated between 13 x l0ˉ6 and 25 x l0ˉ6 is considered high to very high. Note: Another way of expressing compliance is um/mN. Here a rating of 5 to 10 is considered very low, 10 to 20 is moderate and above 35 is very high.