Uh oh. By confronting him, you've just gotten yourself involved in a "Hip Hop Beef". This could in in any number of ways. Rap battle, a dance off, maybe even death. I hope you're ready for this.
Record his behavior with your cell phone. Call the police. Tell them what he said and what you did. Remind them that you have called them time and time again and that you have a record of the number of times that you've called. If something happens between you two, they are liable because they have failed to act. You have at least one witness so, whether he's doing something or not when they get there, you are not lying. When they arrive, go to his door with the police. They can be the mediator of you guys' discussion or they can quit being so penisless and actually give this guy a citation. They've done nothing for so long that this guy doesn't even consider them a threat.
The police sound really incompetent. Incompetent to the point where I would consider kicking in that guys door and destroying shit when he's not around because "They don't have any evidence". Then, I'd tell him that that's what happens when you advertise to the world that you have such a high quality sound system. You tempt bad people to do bad things.
*disclaimer* d21lewis does not condone or endorse the awesome act of kicking in the door of a douche and committing an awesome crime. It would probably solve the issue and be a real adrenaline rush but it's the wrong thing to do. Fun, though.*disclaimer*
