Binaural Electret (Condenser) Microphone

DIY Binaural plug-in powered (3V) electret microphone.

Electret Condenser Microphone: Primo EM272 matched-pair omni-directional.

Microphone Specification –

Note that:

1. You can connect the ground core to the microphone capsule metal shell for grounding.

2.  The microphones operational voltage is between 2-5V with maximum of 0.5mA current. For  supplying the build in microphone capsule’s JFET preamp with 12-48V phantom power supply (instead of 3V plug-in power), additional circuit is needed such as Step-down 5V @0.5mA, DC coupling, filtering etc.

3. Additional insulation may required at the end of the soldered microphone terminal-cable to avoid exposed red positive cable core making contact with the microphone capsule metal shell and other cable cores (= noise!).

The binaural human head size sphere shell is fabricated with PETG through 3-D printing. I will share more information on this once the ‘binaural sphere’ project is completed and officially documented.


  1. Primo EM272 Electret Microphone  (1 set matched-pair = 2x)
  2. Shielded balanced microphone cable (1 meter)
  3. Audio connectors TS or TRS or XLR or Phono or JST (2 unit)
  4. Microphone capsule vent protector – optional (2 unit)
  5. Some solder flux and soldering tools
  6. Heat shrink tube sleeve (50mm x 2 unit yellow color, 50mm x 2 unit blue color)
  7. Multimeter – optional (1 unit)
  8. Head size sphere shell – hollow (1 unit) 

This development is part of Nada Sfera project inspired from Acoustic Commons 2021 Workshop and Locus Sonus