As far back as the Vitascope days, some exhibitors had screened films accompanied by phonographs playing appropriate, though very roughly timed, sound effects; in the style of the Kinetophone described above, rhythmically matching recordings were also made available for march and dance subjects. While Edison oversaw cursory sound-cinema experiments after the success of "The Great Train Robbery" (1903) and other Edison Manufacturing Company productions, it was not until 1908 that he returned in earnest to the combined audiovisual concept that had first led him to enter the motion picture field. Edison patented a synchronization system connecting a projector and a phonograph, located behind the screen, via an assembly of three rigid shafts—a vertical one descending from each device, joined by a third running horizontally the entire length of the theater, beneath the floor. Two years later, he supervised a press demonstration at the laboratory of a sound-film system of either this or a later design.