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Oohlala - first question ever on SSD!

So: I'm wondering if anyone here has experience building and using diy electret mics for field recording purposes? I am thinking of building one of these: http://www.scotthelmke.com/alice-mic.html

Did anyone here build and/or use one of these? How did it fare in terms of sound and, just as importantly, self noise?

I already bought this kit (yet to be built though): http://www.micbooster.com/products/diystereomicroph.html

Which should let me do the spaced omni's thing a bit better than the built in mics on my Sony PCM M10 allows for. The Primo capsules are reported to have very low self-noise, so that doesn't worry me.

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I have. I never bothered building any advanced housings. I focused on placement and also tried various stereo mounting techniques all wit pretty good results. It may not stand up to the very best mics, but mine are far from bad. Make sure for fx recording to get good sensitivity and low noise.

What's great is that the capsules are inexpensive enough that buying a bunch, experimenting and mistreating them until they brake is not a big thing.

  • There's obviously a lot of work in making nice housings, but in the case of the Alice mic (using the Schoeps circuit) it seems necessary with some sort of metal enclosure to keep noise down. Have you tried the Transsound capsules (cardioid), using extra electronics (like in the Alice) - or do you just solder some Panasonics to a cable and go with that? I am going to try a bit of everything, but always nice to hear someone's hard-earned experience. – christiancoriolis Nov 27 '12 at 15:41
  • I didn't use transsound or Panasonic capsules. I bought the best (spec wise) I could find. I can't remember the make right now, but I'm quite sure it's the same ones used in the Sony M10. Very low noise (for electret mics) great sensitivity but does require higher voltage, pip power works but it will not handle high SPL sound without a higher voltage. They are omnis with the pros and cons of all omnis. Price around 10$ a piece. – ErikG Nov 27 '12 at 21:45
  • Found them: BT-EM-172 capsules. – ErikG Nov 27 '12 at 21:48
  • Yep, EM172 capsules are what's in the kit I linked to. I just got them working the other day, and they do seem to match the sound of the M10 very well. Equally low noise, for sure. Ordered some Transsound TSB-165 (Alice mics caps), so we'll see how that goes. – christiancoriolis Nov 29 '12 at 8:06
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I've succesfully build some mics using electret caps. I began with the panasonic wm61a soldered on a rugular 3,5mm plug cable running on pip. It was ok. I attempted the Alice build, but got stuck as the my circuit wasn't working. I've set it aside a haven't picked it up since.

My most recent build is a dummy head for binaural recoding using the Primo em-158 omni caps with a cicuit which provides p48 (which actually gets dumbed down to about 10V) and balanced outputs. This way I can use it with my Fostex FR2. It's basically the Alice circuit with a few changes. Very happy with this one, I get excellent results for such a cheap DIY setup. I've also made a stereo pair version of the dummy in some nice housings to the use as spaced omnis.

I didn't modify the alice circuit myself so schematics and reading material about this circuit are floating on the web.

I have free sfx for download on my website recorded with various DIY setups, should you want to hear some examples.

Some picsalt text http://sphotos-d.ak.fbcdn.net/hphotos-ak-snc7/425001_311230462268252_361607830_n.jpg alt text http://sphotos-a.ak.fbcdn.net/hphotos-ak-ash3/544200_325916204133011_204990475_n.jpg

  • Those are great looking mics, Martin! Did you have them professionally finished somewhere, or is that diy too? Will check out your site... – christiancoriolis Nov 29 '12 at 7:41
  • Thanks Christian. It's all diy. Body is a stainless steel pipe, which I painted just to give them a more pro look. The top is just some thin steel mesh. The inside is filled with isolation material to hold the circuit in it's place and to isolate the mic from picking up sound from within the housing. It's a pretty simple build really. As you can see I painted the dummy aswell, but that didn't work out as planned, couldn't get a smooth/equal finish. Performance wise it's great though. – Martin Nov 29 '12 at 9:23

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