I wanted to replace my Sony MDR-EX51s with some headphones that won't fall apart (see my review of them) and so I purchased these headphones.I could not believe how bad these sound. NO bass presence whatsoever, and yes I tried all three sizes of sleeves. The Sonys are far and away better in sound quality. Anyone looking to move to the Panasonics from the Sonys, at least this model, will be very disappointed.