Headset Issue

Just bought a new headset today (Turtle Beach Stealth 700) but when i join a friend's lobby in league i lose all sound even from other sources like spotify only when i leave my friends lobby or if i change back to my laptop's audio do i get sound back please help!!! P.S. i also dont know much about computers or headsets so that is another issue xD Also i think i posted this in the right section i hope hahahaha if not im sry