I needed to tests this system in order to confirm the status of bug #532958. If you're like me and didn't get an adapter with the system, here is how you can make one.
- 1 cable: 3 RCA plugs to one 4-channel 3.5mm plug - costs about 2$ to 10$
- 2 1/8 (3.5mm) female jack, of the type you prefer (I used chassis) - cost less than a dollar each
Note the type of cable I'm using: it is somewhat important. You could of course use any type of cable with at least 3 wires, but you would then have to find a 4-channel 3.5mm plug, which is a little less easy to find. This cable already has it, so just remove the RCA plugs, and skin these ends to reveal the signal wire and ground.
You'll want to then attach the wires to the 3.5mm jacks as shown in the pictures below.
- Headphone end: use the yellow and red RCA wires. Attach the colored wires to the ring and tip (the name for the metal tabs that carry actual signal when everything is connected, at the bottom of the jack), then attach both ground wires to the ground tab (the tab sticking out to the side).
- Microphone end: use the white RCA wire, attach to either the ring or tip, then ground it.
If the jacks aren't properly grounded or the RCA cable you have used uses a different pinout, you will get no sound, or mono sound, or just very low volume. If so, detach everything and start over, maybe using different color mixes.
Once done correctly, you will retain stereo sound for the headphones, and will be able to use an external microphone, though the internal mic is disabled when this adapter is connected and the setting in Sound Input is at "Microphone". To use the internal microphone instead, you would want to use "Line Input"... but then you probably don't need this adapter and would be better off using standard headphones.
Note: after more research, I found out that an iPhone headset might be the easiest way to go. I however do not own an iPhone, and only found out after finishing up the adapter.