When wiring an electret microphone is using the wire shielding as ground ideal?

Question

Currently with a "single-conductor" shielded wire I have connected the (+) pole of the mic capsule to the wire, and the (-) pole to the shielding strands. I am wondering why the ground wire doesn't also need shielding -- can performance be improved by using a "two-conductor" shielded wire for the (+) and (-) coming from the electret?

My understanding is that shielding acts like a faraday cage and prevents the wires from acting like antennas and passing electromagnetically induced currents (i.e. unwanted interference) .

Answer 1

The - wire of an electret mic connects to its metal case and to the shield of the cable. At the pre-amplifier the shield connects to signal ground. Therefore the + signal wire of the mic is shielded from picking up interference.

Answer 2

Your single conductor with shield setup is exactly how you would do it. You’re shielding the signal from unwanted interference by essentially blocking interference from getting to signal wire and “shorting” that interference to ground. You could use a two wire with shield where positive signal and negative are used with inner wires and then connect negative signal to shield wire. This shield would have to connect to common ground point. This gives the same result because negative signal and shield are both connected to ground.