Diagram of electret mike capsule:
Reality check:
Principle:
How it looks:
About good capsules (better than old Panasonic WM ones)
Check Primo EM172 (10mm element, 14dBA self noise) - http://primomic.com/products/pdf/EM172.pdf
Made a couple of the stereo kits from FEL myself - surprisingly good!
Isn't it a bit big?
Interesting drop in for cheap mics, but yes, it's bigger than tiny.
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.
I've built several stereo mics with Primo EM172 capsules for less than $40. Best affordable electrets ever. I've seen guys around selling custom mics with Primos for $500-$700. They happen work great with the GH2 for ambient pickup. I even found them too sensitive for louder environments. Here's a few samples.
Video for PV channel by @MirrorMan
Thanks to @Vitaliy for encouraging me to do my first tutorial style video. If anyone has any questions about building these mics, ask here and I'll try to answer.
Great tutorial, thank you very much!!
Good tutorial! Thanks to @MirrorMan!
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!
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