RK12 i have measured has more low end than 797 edge terminated and original Neumann. That can be tuned in the circuit. But above say 300hz all three of these are virtually the same.
I agree, even RK12 is closer to Neuman's k67 than other replicas.
However, all the measurements i find online, and published by Sony say that C800's capsule is more like chinese 797 k67 than Neumann's k67.
It has more high and low end, high end peak is higher. All properties of 797's k67.
Here comes heretic statement, drum roll please!
If anyone ever finds direct comparison between Behringer B2 and Sony C800 i bet they would sound almost indistinguishable. And most of the difference would come from headbasket construction.