In an embodiment, articles are left in storage areas, such as lockers or other receptacles, which may be associated with a household services company. The amplitude limiter changes an amplitude limitation rule, which represents a relationship of a limiting value for the amplitude of the canceling signal to the signal level, depending on the vehicle speed, and limits the amplitude of the canceling signal based on the limiting value determined according to the amplitude limitation rule. By making a portion or all of the housing translucent or transparent, ambient light and other external light can be seen by the viewer, providing additional visual cues and a larger perceived field of view. , as the basis of rational therapy.