An acoustic device, including an acoustic enclosure and a first electroacoustical transducing apparatus comprising a motor structure providing mechanical vibration, the vibration having a direction of vibration, mounted in the acoustic enclosure. The acoustic device is constructed and arranged so that first pressure waves are radiated from a first radiation point and second pressure waves are radiated from a second radiation point and so that the first pressure waves and the second pressure waves destructively interfere at observation points relatively equidistant from the first and second radiation points. The acoustic device is further constructed and arranged to be structurally combined with a seating device so that the first radiation point is relatively close to the head of an occupant of the seating device and so that the second radiation point is relatively far from the head of the occupant. The acoustic device is further constructed and arranged to transmit the mechanical vibration to the seat back. |