Hi all, I'm new to the world of ipad having recently just purchased an iPad Mini. The sound seems to buzz/hiss when the volume is turned all the way up. Is this common on all iPad mini's or is there something possibly wrong with mine? I've left the protective screen wrap around it for now, as i dont want it to get smudged, I thought that maybe causing some kind of distortion by blocking the speakers but on the further inspection, looks like the speakers at the bottom aren't really blocked. Thoughts?