I've got a similar situation (although not at this very moment as I'm at work, but i'm a part time student so I have to study at home), so I sympathise. My neighbours play music way too loud, I can hear it over the tv, and sometimes over the top of my own music. I called in the landlords, who said they would write to them, which I think has done the trick.
But if they did carry on, then I'm likely to call in the council as they can be prosectued and fined.
This is the advice that I have been given:
Go round and ask them nicely if they will turn it down. Some noise must be tolerated, so dont expect them to turn it off altogether. OR write them a letter.
If that fails, get someone in authority involved. They should make a formal complaint on your behalf. If that fails then they can be procescuted. (well, thats how it works in the UK!)