How to split all of your audio sources in OBS Studio for full independent control.
Download and Install the CASTER app
In CASTER Live each audio track can be directed to OBS with a dedicated audio device.
To do that, all you need is to enter the track “advanced mode” and turn ON the “Direct to” button.
this will automatically create a dedicated virtual audio device in your Mac and will give it the source track name:
Now all you need to do is go to OBS and select this device as your input source: