OBS probably sees it as a single stereo device. One mic is on the left channel and the other is on the right channel. You can separate their volume and mute controls, but you're stuck with both of them panned to center, and the effects/filters might act weird:
- Set OBS to stereo if it isn't already.
- Make two copies of that stereo source. (4 tracks total, for those who count stereo as 2)
- In the Advanced Audio Properties, check the Mono box for both, and pan/balance them hard left and hard right.
That works because the pan/balance comes before the mono switch, which is backwards from pretty much every physical console. But it does make this trick work.
Effects/filters might act weird, if they come before the panner and mono switch, because they see both signals regardless. This is fine for the EQ and *maybe* for the Noise Suppressor if it's effectively independent per channel; but the Gate, Compressor, and Limiter will respond to both signals instead of only the one that you hear from them. (big spike on Mic A, causes the compressor to drop out Mic B, or the gate to turn Mic B on, when the spike was *only* on Mic A)
If that's not okay, then you should look at processing the audio outside of OBS, and bringing only the finished soundtrack into OBS to pass through unchanged. Depending on how much you need to do, you might be okay with Voicemeeter, or you might need a full-fledged DAW or a physical mixer.
