In about 1913 Duchamp also created a ‘musical erratum’ bearing the same title as the large glass, which also doubles as a theoretical system of music composition. Curiously absent from standard musical reference works, the irregular prerequisites are a funnel, some balls, and a toy train set with open trucks. Each of the balls is numbered to represent a separate note, and the balls then dropped down the funnel, positioned over the track. Chance dictates the order in which the balls drop into the trucks, which in turn decides the tonal sequence of the composition, itself always a random draw. Duchamp expressed no preference for any particular musical instrument, save that it should be of a new type. This version, performed by Mats Persson and Kristine Scholz in 1980, was played on a prepared piano, on which the ordinary action was replaced with a small electric motor and a rotary disc, which moved against the harp strings to produce the singular tones. John Cage would surely have approved.

Marcel Duchamp
La mariée mise à nu par ses célibataires, même (musical erratum)
Version by Mats Persson and Kristine Scholz