Had a weird problem playing back OBS recordings

Open Broadcaster Software was recently superseded with OBS Studio, a complete rewriting of the program bringing with it more features, stability, and a lot more power to record and stream what you want. As I was thinking of streaming this weekend (first time in a long time), I figured I'd try out the new software for myself.

I just wanted to see how the quality would be coming out before being sent through to Twitch or Youtube Gaming, so I just made a few 20-30 second recordings to make sure things were up to snuff. I recorded using my Blue Yeti microphone, doing some audio processing in Reaper and pushing it through a virtual recording device set up by VB Audio Cable. But playing these back had a really weird problem. The audio became heavily modulated and distorted over time. It was horrendous!

Here's a recording of what I heard, played using Daum Potplayer:

You'll notice the volume progressively gets louder and distorted. Recording audio with any other program (like the built-in recorder in Win10) didn't have any issue whatsoever, so I thought it was OBS.

I probably spend 2 hours tweaking settings to try and get to the bottom of this. I was also trying out some real-time audio processing with Reaper, so I thought that could be the problem too.

It turns out though it wasn't OBS at all, it was my playback program! I started using this program called Daum PotPlayer a few months ago. I really liked the interface and felt that it performed better than VLC player, as well as having more control over subtitles. I've never had any problem with Daum before, and I can still watch movies or TV without this issue, but for some reason it really doesn't like the exported videos from OBS.

Case in point, here is the exact same file playing back in VLC player:

And finally, the recording file itself:

No problems! So if you ever run into this kind of problem getting weird audio from your mic, apparently the video player could possibly be the problem. I'll have to explore to see exactly why this was happening. If I find something, I'll post an update