Dieter,

I have 2 KM184 with non consecutive serial numbers.
They are not a "matched" pair, so the first time I picked them
I made this test: with the 2 capsule as close as possible I
recorded a mono source, same gain on mic pres (John Hardy M-1)
then reversed polarity on one of the recorded tracks and monitored in
mono.
Silence.
I think they are matched (well they're matched enough for me!).

Alberto