The noise of longitudinal thin metal film media is experimentally investigated using a new method: the reverse DC erase media noise measuring method. The reverse DC erase noise of thin metal film shows a sharp peak at the field around coercive force Hc. The maximum reverse DC erase noise has a strong correlation to the signal recorded noise. Media with large noise has low D <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">50</inf> and also low Overwrite S/N.