on Windows, to make this work correctly, you will need an audio interface that has 'loopback' capability - if you are live streaming.

My Focusrite 18i8 1st gen does not have this.

I've tried an audio loopback, taking mains out to a couple of inputs - static and crackling.

Or, you can deal with 25ms latency - which is unusable to me. I've been in the OBS forums, the Focusrite FB user group, etc. trying to solve this problem. I've tried every ASIO router add-on, can't get it to work without the major latency issues.

The ASIO plugin for OBS (there is one) will only see your interface's inputs, not it's outputs. So if you are using any processing in your DAW, any soft instruments, etc., you need a way to route them back to an input - or an old-school SB Live card with 'what you hear' option.

-Scott