Which tonearm with a Soundsmith The Voice?

There is no ideal mass. Those calculators are only an estimate anyway, results may vary. You could buy a mediocre arm and have an "ideal" resonance of 10Hz, and it would be outperformed by a higher quality arm where the resonance is outside of the recommended range.

What did Soundsmith say, Schroeder? If that's not doable, you should get as close to that quality as possible within your budget. A resonant frequency of 7.4Hz is not a problem.
Regards,

Go to the vinylengine Cartridge Resonance Evaluator, and enter "11" in the box where it says "effective mass", then look at the table that is produced.

That should help you with a general idea.

8 Hz @ the 22 x 10-6 cm/dyne setting which is the low limit which indicates that an arm with 11 gr mass is still a good match with The Voice. My VPI JMW 12 is I believe somewhere between 11 & 12 gr which wouldn't be too bad!! take in account that (I believe) data from VPI is not reliable, in that, first, it hasn't been published, and when It has been given to me over the Phone by a VPI employee I got the sense that it is not reliable. After 12 years owning this tonearm I still dream with the day when someone will tell me the correct necessary information about this tonearm. Nevertheless, if I go with this tonearm mass of between 11 & 12 gr the combination appears to be ok, interpreting from certain writings that these calculations are just approximations. So, looking for a tonearm with a lower mass, say 9 gr. won't necessarily be and improvement. Hence my belief that nothing compares with direct experience of those who own the cartridge. Yes, I believe the Schroeder would be a clear improvement based on various recommendations and the fact that it appears to be a superlative arm. As far as other lesser arms, I really know nothing, I will try to research the others that were mentioned on this thread online.