Long time bug bear for me and hoping the internet can help!
I would like to stream audio using BUTT ("Broadcast using this tool"). When I start the BUTT app and look at the Audio Device setting I cannot see the internal sound card. All I see is 3 items 1) Default PCM device, 2)Microsoft Sound Mapper, 3) Microphone. BUTT can 'hear' them - they all pick up input from the microphone. There does not seem to be a way for BUTT to listen to the sound routed to the internal speakers.
A possibly associated issue is that if I attach a USB soundcard then - 1 I can listen to sound from that, but BUTT again cannot.