I've never been one to pay a lot of attention to tonearm resonant frequency, and maybe I've just been lucky that it hasn't been a problem. But now I find myself discovering something that is interesting to me, even if obvious to everyone else! I have a Benz Micro LP-S arriving in a couple of days, and it's a heavy cartridge. I was going to put it on a Rega RB330 tonearm, and knowing the problems I had balancing a lighter cartridge on my other RB330, I ordered a second Groovetracer counterweight. In the meantime, my plans changed a bit, as the newly re-tipped Kontrapunkt C on that RB330 has been entrancing me, so I decided it would stay there, and the LP-S will go on an SME Series IV instead. But the Groovetracer was on the way, so when it arrived today, I installed it with the 150g weight (the standard RB330 counterweight is a hair under 100g). I balanced the arm and cartridge with VTF and anti-skate set to zero, then reset VTF to the recommended 2.5g and added back the anti-skate. According to a resonance calculator, this has reduced my resonant frequency from ~8.7Hz to just above 8Hz. It says 10Hz is ideal. But I don't know exactly what the new effective mass is of this tonearm is now, so that's a bit of a guess. The thing is (and I'm as susceptible to psychoacoustics as the next guy), I think it sounds better with the larger counterweight! I'd say fuller bass, but still tight and controlled rather than loose or excessive.
Am I nuts?