It seems many PC gaming wired analog headsets have two separate 3.5mm "TRS" (3-conductor Tip, Ring, Sleeve) phono plugs:
- One for stereo audio output from the PC to the headphones.
- One for microphone audio input from the mic to the PC.
What is the typical pinout for the TRS mic plug?
The reason for my confusion is I would expect the headsets to just have a single mic, so it seems like this should be a mono TS connector (just "tip = signal" and "shaft = shield/ground"), but instead it's a TRS connector, so I'm wondering what the extra conductor is for. Do they just do the one mic's signal twice as if it was stereo? Or do gaming headsets tend to have stereo mics even though the mics can't be placed well for proper stereo separation? Or is the extra conductor for a voltage bias to provide power so the headset can use a condenser mic instead of a dynamic mic? Or to power a preamp so the output comes out at line level instead of mic level?
2 Answers
According to the Intel/Microsoft PC 2001 System Design Guides, Chapter 11 - Audio, requirement AUD-0331, the pink mic-in jack is wired this way:
- Tip = mic signal
- Ring = +5V bias
- Shaft = shield/ground
So a typical gaming headset's pink mic plug must be wired accordingly.
1I found out that on my motherboard (Z270F) and many other boards pink microphone jack is wired in other way to support two channel audio with electret microphones.
- Tip = +3V power & left channel signal
- Ring = +3V power & right channel signal
- Shaft = shield/ground
Simplified TRS mic connection example
Not exactly answer for this question but I think it could help many confused people.
Based on my limited knowledge and some measurements.
