How to deal with a tenant from an apartment across the alleyway who plays loud music on a regular basis?

This guy plays moderately-loud but audible (within my apartment, windows closed) and irritating music (read: 1980’s monster rock on single-track repeat for hours on end, interrupted sporadically with Call of Duty machine gun fire) music every single night. I go to bed at 11, he stays up until 12:30. I’m getting sick of it. I’m not the confrontational type—particularly when it comes to people who live right next to me. I don’t want to be “that guy”—there’s no way for me to politely address him except to yell across the alleyway (about 15–20ft across)—but I want this to end. Any help would be appreciated.