Terrible audio while in-game

When I play with a friend of mine I use discord. The audio from discord is always fine until I get into a game. The audio from the game is perfectly fine but all of a sudden my friend's audio goes extremely loud and the quality is extremely bad. Then after like a minute or 2 the audio from discord goes EXTREMELY loud and ear rapes me even if I have my volume set to the lowest. After the game, my audio goes back to normal with no problems whatsoever which makes me think LoL is the problem and not discord. Not once do I get this problem on other games with my friend except for league. I'm not sure if it's LoL or discord that's causing the problem.