Adjusting iMovie application volume

I'm using iMovie 10.0.9 I also use iTunes a lot, and other applications that have sound, and my computer's volume is set at a comfortable for all of them. However, when using iMovie, the overall volume of the application is much louder than the rest of the applications.

Is there some way that I can adjust iMovie's output volume to match that of the other apps? If I forget to turn the computer down and start previewing clips I get blown out of my chair! Old versions had a volume slider right in the main window, but I can find nothing like that anymore.