Good evening fellows,
So I'm new to streaming and OBS but I figured this out. Please note I'm using the Mac OSX version. It turned out I was set up with "global audio sources" rather than individual sources per scene.
Prep:
If you have your audio mixer set up how you like it take some screenshots of the settings you have and any filters/advanced audio settings you've set up.
Set up:
1. Go to OBS Preferences
2. Audio
3. Under the "Global Audio Devices" section, disable everything and click Ok.
4. Your audio mixer should now be empty of things.
5. Go to the scene you want to add audio to
6. In the sources section, right-click and add a new source
7. Choose either Audio Input Capture or Audio Output Capture depending on the device you want to capture.
8. The new device should appear in your audio mixer.
9. You can now configure this as normal
10. Now comes the magic, switch scene.
11. Your mixer should become empty!
12. Switch back to the scene you added audio sources to, the audio sources should appear in the mixer again.
13. Do a test recording and notice how the audio now fades as you switch in/out scene.
Fantastic, go make yourself a brew.
Yep. I'd add-on to this, a handy technique or two for professional setups.
Number A:
Create a scene called 'MicHolder'. In this scene, add an AIC pointed at your mic. Add this scene to each of your other scenes. Boom! Now if you absolutely DO NOT WANT YOUR MIC LIVE on a given scene, just don't add the MicHolder scene to it.
But why not just add the AIC? Because HOTKEYS, my friends. Each copy of that mic AIC in each scene will need a different hotkey, or each one set manually in each scene in the hotkey list. Adding it to a Scene means only setting ONE hotkey (or two for discrete enable and disable if that's how you roll), and it working on all the scenes.
For 2 (if recording multitrack audio):
Create another Scene, called 'DI'. Add a new AIC to it, pointed at your Mic again. Now add an AOC pointed at your Desktop (and ask Alexandria how she got into your house). Assign these to their own Tracks in the Advanced Audio Properties, and NOT to your Stream Audio track. Add this scene to ALL of your scenes. ALL of them.
Boom, you now have Direct Input feeds. Leave off any filters you add to your mic or desktop for the stream. Never lose audio when you mute, so you can put it back in when you're editing! A
clean audio feed, 1:1, so when you're mastering audio and setting the levels and normalization, you don't have to worry about all that realtime best-guess stuff.