cartiage for Kenwood L07D genuine tone arm

thanks for reply
I might uses a EMT JSD or lyra kleos on it
hope they can work well

As with cartridge weight, the mass and distance of the counterweight from the pivot point certainly changes the effective mass/inertial mass of the combined system.

With all due respect to Johnny, and as Dave partly indicated, Johnny's response to the question about effective mass is incorrect on all counts. The effective mass is a function of the distribution of the mass of the tonearm from pivot to headshell, including the cartridge mass, (not just the total mass per se), which is why you cannot determine effective mass by simply weighing the tonearm, and the counter-weight also contributes to effective mass by a factor related to the square of the distance from the pivot point to the center of mass of the CW times the mass of the CW. Thus, the "subweight" increases effective mass on both counts; it shifts the center of mass of the total CW further away from the pivot and it adds to total mass. Apologies to Johnny...

Since the effective tone arm mass is not simple measurement
If I change a aftermarket headshell, how it will change? Can I ausume it add or decrease the difference only?

Jagdzaku,
To answer your question, almost. With mass behind the position of the cartridge, 100% of the weight difference does not subtract or add to eff mass. This is a trivial amount. The stock shell looks to be of very high quality, but it might be interesting to experiment.

To clear up some misconceptions, if you increase the weight of the counterweight and bring it closer to the pivot, eff mass will decrease with the change of distance.

I think too much emphasis is placed on resultant resonant frequency. IMO you'd be better off asking users which carts are a good match, which combination seems like it's made in heaven. Some carts seem to sound better with mass that puts them a little out of the recommended resonance range. While you don't want that undamped resonance approaching the audio band or excited by a warp, best results are not defined by "perfect" 10Hz resonance.
Regards,