I feel for you really I do.
Before we moved into our new house we lived in a duplex for a year and a half. For a year and 5 months it was great, then we got new neighbors. Now I am a very tolerant person, I mean it is New Orleans so you have to expect a level of craziness. I've lived through lots of things and tolerated them and nothing compares to these guys. To start with they were in a band, that practiced 2 hours every other day. Ok, fine I can deal with that. However, they played techno music about 10 hours of the day, every day, on their amplifiers at ungodly levels. Imagine trying to study or go to sleep or even watch TV through that. And every day it was the same---at 5 in the afternoon it came on(when they woke up), and was pretty much constant until midnight(when they went out to the clubs), but what was worse was that at about 4 AM they would turn it on again for a couple of hours. I tried everything. I called the cops, I called the landlord, I pleaded with them, I tried politely asking them, I threatened them(and I'm 6 foot 4 and an athlete--threats always work for me), and I even tried to get back at them. Nothing worked. After one week I was fed up and in about 3 days we found a house to rent and move into. Luckily we were on a month to month lease and friendly with the landlords and thus had no trouble with the move out. Basically those guys taught me that some people just have no decency and nothing short of moving out will solve the problem. Just feel lucky that you aren't having this happen 1 month into a year long lease.
I would say this, if there is drinking going on at the parties just call the cops, the actual police not the courtesy cops, and keep calling them(basically annoy the cops until until they break up the party). Also if you know your neighbors tell them to do the same thing. There's nothing like having cops at your party every 30 minutes to kill the party atmosphere. Plus the cops get annoyed at being called all the time and since they can't take it out on you they will take it out on the party goers. However this does not work well in some large cities like New Orleans, LA, NY, etc. where the cops only respond to robberies, rapes, and murder.