Soooo, if/when asking the neighbor nicely doesn't work.... my suggestion is to go to your local cheap/used CD store. Pick up a CD of scottish bagpipes. When loud music starts, turn your speakers towards the adjoining wall, press play, and turn volume up. I found this works equally well with loud spanish karoke (my current neighhbors) and loud rap music (former neighbor). Hmmmm, who woulda thunk that so many people don't enjoy scottish bagpipes?
We called the police on very loud neighbors recently and they said we know you called the police and you will get yours .
OMG that's scary! I've called the police on my neighbors when I lived at my parents house, and I used a cell phone and when the person on the phone asked for my name, I just told them I wish to remain anonymous. It's perfectly ok to say that and they'll still send the cops.