I know this is an old question, and i dont know if im allowed to state 3rd party programs; but i found that 'voicemeeter banana' and 'audio router' can help you redirect all the other sources of sounds into a virtual source, leaving your obs sources in another. Hope that helps anyone else searching for solutions.A way to change browser source audio output would be nice so it doesn't mix with desktop audio or better yet a way to change any and all source(s) audio output would help
How to apply routing? I ticked the "control audio via Obs" but what happens is that sound is gone.From OBS 24.0, you can now control individual browser audio in the mixer as well as apply routing. Just be sure to select "Control audio via OBS" in the browser source's properties.