Jack Fairley wrote:OBS doesn't have any monitoring of audio from capture devices. You'll have to handle it on the OS level somehow, by duplicating the audio input of the BMD card to the output device you want to hear it on.
When using an Elgato, OBS can pipe audio to desktop (and then you can capture from the monitor of the desktop audio, but this induces a slight delay, but that's OK because you can compensate for it.)
I guess the Blackmagic plugin just doesn't support that sort of shenanigans.
I'm looking at my pulseaudio devices, but I cannot find Blackmagic in this list in order to duplicate it as you suggested:
https://pastebin.com/iHEKEx5sDoes it show up elsewhere? (Is it only present when Blackmagic is capturing? I'm not physically present at my computer so I can't test it.)