I noticed that the Sennheiser ME series (ME-20, ME-40, ME-80 etc) used to be popular in the old days.
But looking at the frequency curves, they all drop off at 15,000Hz, which doesn't seem optimal for taping?!
http://www.sennheiser.com/sennheiser/old_manual.nsf/resources/K3N.pdf/$File/K3N.pdf
Was there a particular reason for running these caps anyway?
Or was the stated specs too modest, with the mics performing better IRL?
I believe the K3 are the predecessors to the K6 system. As far as quality of caps go, these could be pretty good. They are electret. I've tried the KE10 capsule, which is in the MKE40 lav mics, and also the one at Microphone madness. This is very nice sounding, but a bit lacking in bass. These capsules (and the newer K6) appear to have the KE14 capsule, which has lower noise, more bass, and *probably* good sound, though I have not tried it.
Interesting to see this K3 series shown as "actives". I'm sure it is easy to run the K6 series in the same way, with a battery box. I *almost* bought the K6 heads on sale recently, but did not need any more distractions at the moment.
Oh yeah, 15kHz. I would not worry about it. Once you're over 30yo you won't hear that anyway. Stand near an old (tube) TV. Do you hear the high-pitched whine (15.x kHz)? If not, you won't notice it in your recordings. You'll see the 15.x kHz spike in the spectrum of your recordings though...
Richard