Have you tried talking nicely to them? Kind of a crazy concept... But when my husband was working nights and sleeping days, we lived by someone that listened to thumpthump gangsta rap during the day. Asking them nicely if they wouldn't mind keeping it down so he could sleep worked. :O

I second everyone saying to 'ask them nicely'. Politeness and sincerity can go a long way where threats can't. Try to reason that as an individual, you're entitled to a full-night's sleep without disturbances and that they are creating disturbances which make it hard for you to sleep. Tiredness can cause lackluster performance at a job or school, can cause you to have bad judgment, fall asleep at the wheel, etc and stress how important it is that you be able to get a full night's sleep.

If that doesn't work, go to the landlord, or to the authorities.

Yeah, that's gotta be crazy.

I mean, even I'm a JESUS FREAKKK! and yet, I would NOT want to wake up to that.

Ugh.

Be polite when asking them. If I was blaring my screamo and someone threatened me to turn it down, I probably wouldn't. On the contrary, if someone asked me politely, I would have more respect and turn it down.