SERIOUS PROBLEM! Can you tell me what I should do?

I have really loud next door neighbors and I live in a duplex...they play really loud music all the time and they're b sounds a really loud. I can't sleep at night and yesterday they were holding a party it was soooo loud...is this a crime, can I call the police? Does this count as a disturbance at night? Who should I go to? I've already been to that house 3 times to tell them to please turn down the volume, I can hear them next door but they refuse to take in my humble request. Please Help me!