Why the hissing noise

This is a problem that I have seen - or should I say heard - in many other movies as well. Randomly, a loud high frequency hiss issues from some scenes. I believe it is due to the recording; the hissing occurs only during the parts where they have to dub new audio recorded in the studio, replacing the audio originally recorded on-scene. The mic they use for this studio recording must be very bad and produces a loud EEEEE! whine.

Old people can't hear above a certain frequency, which would explain why this wasn't taken out. The process to take it out is extremely simple and takes 2 seconds with a simple EQ that removes frequencies above a certain threshold.

Solution: Have young people with good ears preview this film before releasing.