Vedder

Hi Everyone, I have had a Net MD MZ-N505 for about 18 months now, I'm happy with it until recently were it does not seem as loud as it normally was. I thought the first thing would be the battery being flat so I put in a new one and it's still the same. I have not dropped it or anything and was wondering if this was a common fault in these players and how I could go around fixing it? thanks for your time