Can't remember the name of this movie I'm looking for.

[madpoetress]

Okay so the other day I woke up and turned on this strange movie. Not sure what it's called but now I want to share it with the rest of the family and my friends and it's driving me crazy. I assume the genre is probably science fiction. It involves a group of people, one of which I know is a doctor of some kind probably a psychologist, go into this town and follow a trail into this field/wooded area. They have 4 wheelers, compasses, camping gear, food/water, and gps systems. The compases and gps don't seem to do any good, it shows that they are crossing over large masses of land on the gps like from one country to another which they obviously are not. Apparently at some time in the movie they found a journal from the town that had been there before. The townees had evidently walked down this path, kept walking because they heard "music" and never returned back. Well the longer the people are in this area they can't find their way back, they become forgetful, they don't remember the day before, and they keep hearing some odd music playing just in the air. It sounds as if it's being played on an old old music player, but there is nothing around to play the music and no where for it to come out to be heard. They eventually start killing each other, and stealing from each other, and cheating on each other, etc. On scene I can recall very vivdly was with a man and this woman they were in the group and they were arguing amongst each other. She gives up arguing with him and takes off walking, he decides to chase after her. Once he gets up to her he knocks her down and beats her head in.

If you could help me out it would be greatly appreciated, very strange movie, but it was interesting to say the least.