iMovie--change in sound volume


Hello. I'm working on a project in iMovie and have imported music from iTunes.

Very strange. At one point in the project--about 9 or so minutes in--the sound from the audio clip suddenly drops to about 15% for 15 seconds. Then, just as suddenly, it comes back to the normal level.

This doesn't seem to have anything to do with what is happening in the project. I can import a photo or a transition or a text page or a video clip--the sound still changes at that particular time into the project and for the same period of time.

Also, it doesn't seem to be have anything to do with ducking. The drop happens in the middle of still shot and then changes back in the middle of a separate text image.

Would greatly appreciate any insight anyone has.

Thanks much.