Made a couple of the stereo kits from FEL myself - surprisingly good!

@DrDave

Isn't it a bit big?

@DrDave

They advise to put it into big condenser cases, as it won't fit inside any pencil mikes.

Also note - it is easy to make low noise large capsule, but with size reduction self noise always rise all else being equal.

Video for PV channel by @MirrorMan

Great tutorial, thank you very much!!

Just came across this well produced tutorial today while searching for a PASSIVE filter design to add inline to a tiny electret. I'm upgrading a vintage headset's boom assembly to fit a tiny low-cut (high-pass) filter; wiring DC into this assembly is not an option so it must be a passive design. The frequencies I'd like to emulate are those of a vintage crystal element, prominently used on AM at that time. Because the headset will be used in AM mode, my ECM's native spectrum produces very muffled audio when on AM - as I cannot adjust my transceiver's internal filtering stages, I'm left to focus on modifying the audio input range of my headset instead. I'm considering using a Primo ECM cartridge instead of the standard ECM I have, but for now, I just hope to find and add the values of R and L inline to come as close to a crystal element's range as I can. It must be painfully obviously I'm not schooled in this field - I'm merely working with what knowledge I'm sponging from the internet so I'm always grateful for guidance from the Community. I'll appreciate any online references to such a build so I can calculate the values using the ECM I have to work with before having to escalate things. Best wishes to all - Stay safe!