Automatic musical instruments were not only used as devices for the performance of existing musical pieces. Composers also saw possibilities for realizing things with the new machines that had not been possible with traditional instruments. Paul Hindemith (1895-1963) was one of those composers. He joined a collaboration project with the Welte company, where composers wrote their pieces directly onto the piano rolls for the Welte-Mignon reproducing piano. Hindemith’s works, together with the works of two other composers, were “played” on the last day of the Donaueschiner Kammer musik-Auf füh run gen, a German festival for new music, under the title “Aufführung von Originalkompositionen für mechanisches Klavier (Welte-Mignon).” Their pieces abound with broad sounds that could never be produced by human hands. But more important, by renouncing the intervention of a human performer, a clear coolness that could only be achieved by machines opened new perspectives for musical expression.