pMic

A printable A-B-Stereo Microphone

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I wanted to have a mic which I cought use for general purpose recording in conjunction with my old iriver h120 (with rockbox installed). I didn’t found a suitable mic without a build in recorder:)

So after a little bit googleing I found this article about a low-cost homebrew solution and decided to get a bunch of these panasonic wm61-capsules described in the article to start experimenting with them – here is the result.

A special feature of this microphone is it’s variable stereo width (by time-of-arrival stereophony).

The button near the audio jack is the on/off-swiitch, the second one a gain boost. By swapping two resistors in the circuit, the gain boost could be easily converted to a gain damp. The preamp circuit isn’t necessary at all, if your recorders preamp has phantom power. But the 9v battery increases the headroom for louder signals and powers the 4 capsules more convenient. The distance between capsules and preamp shoud be as short as possible.

I’m quite happy with the sound. Here are some audio examples: https://github.com/Piesi/pMic/tree/master/docs/audio_examples

You can download it here:
http://www.thingiverse.com/thing:186913
or here
https://github.com/Piesi/pMic

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16 thoughts on “pMic

    1. Hi Jesse,
      the capsule case is only 1.5 cm thick, while
      a sonic wave at 20kH has a wavelength of about
      1.7 cm. So from what I’ve learned about propagation of sound, the wave should lean around the sides of the case. I made a quick and dirty test and didn’t notice any change of volume as I turned the mic around…

  1. Would you sell me one of these? I dont have access to a 3d printer and I dont trust myself assembling electronics. I blew up my 606 drum machine trying to modify it 😦

    1. Hi Zak,
      yes, why not. I don’t know what to charge for this yet. So, I’ll write a bill of materials on the weekend to calculate what the production costs and then call you back…:)

      1. Awesome! Thanks Piesi.
        If you would like to include the shipping in your bill I live in Adelaide, Australia, SA, Postcode 5000.
        Look forward to hearing from you 🙂

    2. Hi, I’ve just added a BOM to the git-repository. I decided to go with four price options you can choose from:

      pMic Basic (without preamp):
      diy kit: 25€ + shipping (to australia 15€) = 40€
      assembled: 40€ + shipping (to australia 15€) = 55€

      pMic Preamp:
      diy kit: 35€ + shipping (to australia 15€) = 50€
      assembled: 70€ + shipping (to australia 15€) = 90€

      The assembly of the preamp is the most complex and thus
      expensive part, since I have no machinery to make the pcb.
      But as I mentioned, the preamp is not necessary. I’ll make
      a non preamp version (but with 9v phantom power)and add
      audio examples for that, so you can hear if there is a difference.

      1. This is probably a pretty stupid question but I’ll ask anyway. I noticed that you use a 3.5mm Jack. Does that even work with phantom power? (I am under the impression that phantom power requires an XLR connector). I’m talking about the basic, no preamp version.

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