We have an Apple TV and for some reason it is not only is it quieter than anything else plugged into the TV sound system, but it seriously appears to be quieter and quieter and quieter every few months, so that we're constantly having to turn the tv up louder and louder for the volume to seem normal and we finally can't turn it up anymore. Can anyone think of a reason this might happen? I have all the dynamic volume adjustment/"make voice clearer" stuff switched off.