iPad 3 speaker distortion

Just went to watch something on the BBC iplayer and the sound at nearly full volume was distorted and tinny, backing it down to about 75% was ok thinking it was something to do with a faulty download from the beeb I tried another app for films and was exactly the same, this has only just started to do this, plugged the iPad into speakers and it sounded fine its a little over 4 months old.

I have read in other forums about this but only seen questions and no answers so don't know if its a fault with hardware or software, might have to take a trip to my local apple store... Unless anyone has any suggestions.