When I INITIALLY set up the monitoring (5 months ago), I was indeed using the ElGato recording software. But since it's limited and gave me problems, I moved to OBS some 3 months ago.
For 3 months OBS worked perfectly (after a week of fiddling around to set it up xD). Then, as I said, I closed it 6 weeks ago after recording a video, and upon opening yesterday it was already not working.
Not sure how this would help, but I guess that answers your 2 questions.
Also, I should add two things. First, I tried using ElGato recording again for test: got the audio no problem as soon as it launched.
Second, I tried OBS with headphones AND with the loudspeakers. None works.
These things make me think that it is, in fact, an OBS issue, not CC issue or headphone issue. I could try to download XSplit or something to check a THIRD program, but I mean... I've already confirmed that ElGato recording works and OBS doesn't.
Also, as a side note, the "Check out the video device properties of the Capture Card within OBS itself " thing. That's not really a solution. I can change the Audio Output Mode from Default to Desktop Audio (WaveOut) [DirectSound sounds crappy]. If I do that, I obviously can hear the game again.
But there's 2 problems with that.
1) When I finish the recording, since the game is in the Desktop audio track, ANY sounds I may have had during recording (discord notification, windows notification, antivirus notification) will be included in the recording. Not good. And if someone says "well, you can mute notifications", that's not a solution either because:
2) Even if that worked, it still doesn't solve the issue: WHY did this magically stop working during the 6 weeks that I did NOT use the program? I didn't change any settings.
And anyway, I don't want to mute notifications. That's like a bandaid for a bandaid. It was working 6 weeks ago, so I shouldn't have to change literally 15 settings (Obs AND Windows) so it works again.
And finally, a super final extra. After MUCH horsing around, I tried creating a new Scene Collection. Since the new collection had no Source initially, there were no audio tracks in the mixer. When I changed back to my default collection... MAGIC! Sound was working again.
...except after 30 minutes it stopped working again. This point I can't clarify further, I fear, cause I honestly can't remember what I did. I was still touching stuff trying to make it work. I know I didn't stare at the screen for 30 minutes, but WHAT I did that made it stop working... no idea.
Still, this is not a solution, it's another oddity. There's no reason why it should've stopped working in the first place, and no reason why changing scens and changing back should've fixed it, so...
Also, I tried doing it again (change scenes back and forth), 5 times, none worked.
EDIT: So I tried again today after writing this. On launching OBS I had audio... but no video. Fantastic.
However, re-launching made everything work. For some reason.
So I kinda sorta spent 10 hours today unable to work and fiddling with OBS settings, trying to fix a problem that shouldn't have happened in the first place... only for it to fix itself the next day.
Gotta love technology sometimes.
Well, whatever. I'm not sure if I'm the one supposed to close this thread as "solved" or a moderator or what, but please DON'T close it. Since the problem appeared and disappeared magically, I'm expecting it'll magically appear again sooner or later, so it'd be kinda dumb to have to open a new thread. At least let's keep this one a few weeks.
EDIT TWO: Well that didn't take long. I closed and opened OBS 5 times while testing, and problem was gone. I open it now, 2 hours later, to start recording streaming... no audio again.
