fucking assholes and their god dam loud music!i hope they die
Check out the noise regulations in your area. Most places, you can't play loud music after a certain time (it varies from 10 PM to midnight depending on the place). If they violate this, call the police. They can issue a citation. Enough citations and the police will have to let you press charges.
We did this and our neighbors eventually were ordered by a judge to wear headphones. Naturally, they moved.