I saw this weird movie as a kid. It is focused on a man who is trapped in a cult and includes a lot of outdoor scenes. I think there might be some invisible dome that keeps people inside. There are lots of people there who have given in to the cult and they do a lot of chanting. There is also some ear piercing sound that the cult members create with their chants which sends the guy mad.  The people might also be wearing some uniform. Could have been a TV only thing, no idea.