I just got my new iPhone yesterday. So far so good although I just ran into an issue. When I'm on the phone talking I'm getting a weird buzzing / rattle from the earpiece speaker. Almost sounds like the speaker is a bit blow. I really notice it when calling and getting the "ring, ring." And when the person talking on the other end gets a bit loud. I've never noticed this before on my 3. Anybody else getting this? What should I do?