My loud neighbors.....s-e-x or assault?

So i live in NYC. and i can hear some one upstairs haveing intercourse.......it is loud and goes on for a while.....
its also disturbing.
the noises sound almost forceful...i think the people might be nuts......how do i get them to either stop having such loud sex, or find out if they are just tourchering eachother up there...seriously i am disturbed. I alwasy here news stories about people breaking into apts and raping women for a couple of days. the media makes me paranoid....and their sex noises are CREEPY. whats teh best way to detrmine which apt the noises are coming from and if its legit intercouse or assault? jeeez.
Complain to the apt. manager about the noise. They'll never do anything about it though.
Don't be this guy:

http://emuse.ebaumsworld.com/video/watch...

The man in this clip was arrested for breaking into a neighbor's apartment to stop what he thought was a forced sexual encounter. What he found was his male neighbor watching porn. Just bang on the wall/ceiling like a normal neighbor. If that isn't your cup of tea, just call the cops for noise violation. They'll determine the nature of the noise.


Answer:
I’m not sure why people always tell you the obvious, like telling the building manager or calling the cops, like you haven’t done that already. Just remember if you can hear them, they can hear you. I recorded the loud noises my neighbors made and played it back at a very loud volume several time. To get my point across I played it at different times. They were so embarrassed they moved out with-in days.
Have the cops come out and take a listen. Tell them you here a woman being tortured. They'll come quickly.