Motorola RAZR V3m

This is a random question about the Razor V3m. I got the phone about two days ago and I was playing around with it today when I noticed something. When I fliped open the phone and just put it up to my ear (as if you were making a real phone call) I noticed that I heard a high pitched tone. It must have been the screen because when I pushed the screen back just a little bit the tone got louder. Does anyone else experience this?