The Reliability of Tonearm+Cartridge Fundamental Resonance Charts/Calculators

[Al Stewart]

@mtemur Understood.

 

[Ron Resnick]

Would someone on this thread expert on the topic of cartridge/tonearm compatibility please kindly accept the assignment of evaluating using these charts/calculators the likely compatibility and sonic success of the Grado Epoch3 cartridge on the Bergmann Odin tonearm? When I do this I conclude that the match is questionable, and uncomfortably close to an extreme end on the line on the chart.

Thank you!

 

[mtemur]

Would someone on this thread expert on the topic of cartridge/tonearm compatibility please kindly accept the assignment of evaluating using these charts/calculators the likely compatibility and sonic success of the Grado Epoch3 cartridge on the Bergmann Odin tonearm? When I do this I conclude that the match is questionable, and uncomfortably close to an extreme end on the line on the chart.

Thank you!

resonance frequency calculated as 6.91Hz, but I highly suspect declared 20μm/mN compliance number cause it is too high for a cartridge with 12g weight. there is a close relation between cartridge mass and compliance like a car's weight and suspension. manufacturing a compliant and heavy cartridge is like putting sedan suspensions on a truck. that doesn't make sense.

IOT achieve sensible 9Hz resonance frequency that Grado cartridge requires a tonearm with an effective mass of 3.11g. which is ridiculous. that's why I guess Grado's dynamic compliance at 10Hz is around 10μm/mN. in that case calculated resonance frequency for your cartridge an tonearm becomes 9.78Hz.
on the other hand Bergmann Odin tonearm can be used almost any cartridge with it's 14g moderate effective mass. I haven't listen to Grado Epoch3 but I listened to Bergmann Odin. it is an airbearing tonearm sitting on a spongy air cushion. if you have loose bottom end or lack of impactful/thunderous bass it may not be because of out of chart resonance frequency.

 

[Ron Resnick]

Thank you very, very much for performing this analysis! I truly appreciate it!

 

[Al Stewart]

@Ron Resnick FWIW Grado's website lists the Grado Epoch3's Compliance: 20μm/mN.

I'm not sure why Grado would list this compliance number if it was in actuality 10μm/mN. Grado doesn't say whether their reported compliance is at 10Hz or 100Hz. If at 100Hz then the number would need to be increased (by a factor of 1.5X according to some) not decreased. Why wouldn't we rely on what Grado reported the Epoch3's compliance to be?

I'm not advocating that @mtemur isn't correct in his assessment of the Grado Epoch3 compliance number. I just don't know how he got there and I don't understand how or why Grado would report it incorrectly.

What this thread (so far) seems to demonstrate is that the declared compliance numbers may not be reliable and the published tonearm effective mass numbers may not be reliable. Damping also may play a factor and apparently isn't taken into account by the calculators. If the inputs aren't reliable, then why is using a "calculator" a good idea?