A passive noise reduction apparatus for altering predetermined sound levels of a sound producing device, the noise reduction apparatus includes at least one piezoelectric foil sensor disposed relative to the sound producing device with the at least one piezoelectric foil sensor being operable to convert such sound wave energy into an electric sound signal and one or more electric circuits in electrical communication with the at least one piezoelectric foil sensor for receiving the electric sound signal and shunting the electric sound signal to a ground connection, thereby reducing sound heard outside the sound producing device.