In an attempt to cheaply reproduce something like the
Cooper Time Cube, I need to interface two electret microphones to XLR3 mic connectors.
This page
http://www.epanorama.net/circuits/microphone_powering.htmlgives two schematics, one titled balanced electret microphone circuit, and one better electret microphone phantom powering circuit.
Or I wonder if I should just get something like this
Electret Microphone Amplifier - MAX4466 with Adjustable Gain from Adafruit.