Electronic amusement devices shall be permitted as accessory uses to a principal commercial use, at a ratio of one amusement device per 400 square feet of area accessible to customers within the business. This minimum ratio shall not apply to a use that is approved as an amusement arcade. For the purpose of this section, kitchens, storage areas, rest facilities, office areas and passageways shall not be included in computing customer accessible area. Each public and private restaurant or tavern, regardless of its size, shall be permitted at least two amusement devices. No amusement device shall be audible beyond the premises within which it is located.