Muffled Audio With Headphones

I like to have a video playing on my external monitor (YouTube, Twitch, etc) and play games on my main display. Whenever I do this and have headphones connected, the audio for whatever is playing on my external monitor becomes extremely muffled and sounds terrible when I launch a game. When I then quit the game, the audio quality reverts to sounding normal. Does anyone know a good solution to this problem? I’ve tried a lot of the obvious troubleshooting options.