Disclosed is a golf ball having a cover formed from a thermoplastic polyurethane material which can be recycled for molding, which exhibits high restitution, and which exhibits excellent scuff resistance. The MEMS device may include a first plate, a second plate and a third plate. The holder includes an electric conductor that electrically connects the electrode of an image bearing unit and an electrode of a power supply when the holder is closed. The two specific terminals constitute a terminal pair for transmitting differential signals. The adaptive filter determines the inverse of a synthesis characteristic from the headphone to the sound-collecting microphone based on the input sound signal and the difference, and sets the determined characteristic as a characteristic of the correction filter.