Welte & Söhne, Freiburg/Br. 1904
Lender: Technisches Museum Wien
128 x 52 x 102 cm, ca. 100 kg
Wood, rolls with perforated paper tape, controlled by lead wires, leather valves, rubber cloth bellows, electric air-pump

Push-up play music rolls in the same way as a complete mechanical piano, but using an existing instrument. The roll is “scanned” using air sucked through a “tracker bar”, the perforations in the roll corresponding to the positions of the keys on the piano, while the dynamics of the notes are recorded in the margins of the roll. The keys are depressed by levers activated by bellows that are evacuated and filled with air in accordance with the position of the hole.