Management of my building has not resolved a long-standing noise issue I have with my neighbor. Can I break my lease?

I have a noise problem with my neighbor that the management company refuses to resolve.  I hear the neighbor's surround sound tv/gaming setup all day and night.  I've asked him repeatedly, verbally and in writing, to turn down the sound. Management made a weak attempt at mediation, only to send a letter stating they determined the neighbor wasn't loud (despite management visiting my apartment and verbally agreeing it WAS loud). The other night the neighbor was being loud, and I knocked on the wall to let him know I was home and could hear him. He responded by harassing me by turning up his system to full volume repeatedly and pounding on the wall until I had to go elsewhere to sleep.  Is this "quiet enjoyment" violation and can I break my lease? If so, how much notice must I give?