heck I'd set up my own system and make sure it pointed towards him and
then put on some high class classical and make sure it was louder than
his and let it rip.

I did just that - using Wagner to fend off some particularly repellant (c)rap
music from the neighbour. They got the message pretty quickly.

A friend had an even better solution. He called his mother, who called the
mother of the 30 somethings next door, who called her children (well that's
what they were acting like) and told them to cool it.