2 points
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What do you mean by stereo wire? It’s got 3 contacts on the 3.5mm jack, that’s enough to transfer analog stereo (GND, L, R).
5 points
7 points
It’s for bias to the mic. Condenser mics need it to apply bias to one of the leads of the mic so it can amplify the sound before sending it to the input of the card. Some mics don’t require that (self-biased) so in that case, the R pin (middle ring) goes to GND.
1 point
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Ah, seems you’re right. I didn’t know that. But that seems to be an old way of doing it. I’ve only ever seen 2 contacts on a seperate microphone jack or the 4-contact combined ones in modern laptops.
