Am I loud?

I was subbing in a 4th grade class today. The kids are all very nice, though very chatty. As such if you let them talk too much the volume has a tendency to go higher than it should. I shocked most of the kids in my class when I bellowed to get their attention. As they quickly learned, I can and WILL be louder than they are to get their attention and that they need to pay attention when I do. It appeared I caught the grudging respect of a few of the kids as a result.