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Tonearm effective mass

I have read about and think I have a basic understanding of matching cartridge compliance and tonearm effective mass.  I also have read a bit about how effective mass relates to moment of inertia, and how one can alter this by different combinations of counterweight/pivot point distance.  What I havent seen, and I would think would be easier, is the effect of adding extra weight, ie heavier screws, in attaching the cartridge to the headshell...would this not, as well, increase the effective mass/moment of inertia?  .help in understanding this would be appreciated...thank you

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russ69's avatar
russ69
3,497 posts
 

Moment of inertia Is seldom used to determine cartridge compliance mostly due the complexity of this calculation. The manufacturer might have done this during design but not very practical for field cartridges installation.   

jasonbourne52's avatar
jasonbourne52
2,863 posts
 

Adding weight lowers the resonate frequency. 

russ69's avatar
russ69
3,497 posts
 

P.S. It's not really rocket science because you basically have high compliance or low compliance cartridges. A quick call to the tonearm manufacturer will help with cartridge selection as will seeing what cartridges the factory can supply with their product.  

audiosaurusrex's avatar
audiosaurusrex
320 posts
 

@yogiboy 

trying to understand this a little better with my Acoustic Signature 12”

TA-1000 tonearm. Maybe I’m not seeing the right specs for the two cartridges I’d like to pair, Umami Red and AT-ART9xa. 

yogiboy's avatar
yogiboy
5,654 posts
 

The AT-ART 9xa shows a weight of 8.5 grams and compliance of 20x10-6 at 100hz. The Umani Red does not give a compliance spec. BTW, Japanese cartridges compliance figures are not at 10hz they are at 100hz so you will have to multiply by 1.7 to get the correct resonance frequency calculation figure. With your 12 gram tonearm and that ART, the resonance frequency is 6hz!

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