What is the most effective way to get our neighbors to turn down their music, sound levels?

I just moved into a new 3 br apartment with my roommate and we love it, covet it. Our neighbors have packed 5 into their apartment, have some synth band and are in their mid-twenties. We knew about them, and their noise, before we moved in.

At times they have band practice in the basement. At times their music is just too loud. Generally, I hate them. Right now, bass is filling my bedroom.

Now, I’m not yet 30, but this drives me nuts. Blaze your trees, do what you do behind closed doors, but noise pollution sucks.

My roommate and I don’t want to negotiate with them, i.e. “could you turn it down a bit please?” We don’t want to be daddies or coddle them.

We just want it to stop and I am looking for creative ways/suggestions to do so. Help!