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Motion Music Machine (Sonar)


Lucinda Childs, Vehicle
Tool Identification

Name of tool: Motion Music Machine
Alternate name: Doppler Sonar
Creation date: 1966
Designers: Peter Hirsch, Manfred Schroeder

Historical Notice

The sonar was developed by Paul Langevin in 1917. It allowed information to be transmitted and received underwater. The main objective (with the Titanic catastrophe still fresh in everyone’s mind) was to detect submerged obstacles.

The Doppler sonar was the first project noted, in February 1966, in the list drawn up during meetings between the artists and engineers. (1) Manfred Schroeder, then director of the Acoustics, Speech and Mechanics Laboratory at Bell, proposed this solution: “I became involved because I am familiar with all kinds of sound effects. Acoustics is my speciality, and part of my endeavour here was to integrate acoustic effects into these performances. Dancer Lucinda Childs was asking for things to translate body movements directly into sound, so that she could actually create her own accompaniment as she danced. We came up with a device that reflected ultrasonic waves from her body, then converted them to audible sound. I got the idea from work I'd done years ago on stabilizing public address systems, and feedback problems with the Speakerphone, which under certain conditions produced howling or singing noises. It wasn't a very interesting sound. But while we were working with it we discovered that it would make all kinds of funny sounds if you did the right things to it and if people walked through the room. When Miss Childs made her request, I remembered that work. But, it needed some artistic concept to make it worthwhile and enjoyable.” (2) The Doppler sonar, dubbed the “Motion Music Machine,” was subsequently developed by Peter Hirsch, a specialist in underwater sound.

Tool Description

The Doppler sonar was composed of a high-frequency ultrasound transmitter and a receiver.

Summary of Materials

Receiver and ultrasound transmitter.


Receiver and ultrasound transmitter.

Operating Procedure

A transmitter produced pulsating sound waves lasting just a few milliseconds. The frequency of these waves could not be heard by the human ear. When a moving object interfered with the propagation of the waves, they would be reflected back towards the sonar receiver, which was placed next to the transmitter. One would then hear the proportional difference between the frequencies emitted and those received in accordance with the speed of the object or body in motion (Doppler effect). The transmitter was installed so as to throw a beam some 20 feet, which scanned the area between the performer’s waist and shoulders. Movement of the arms, torso and assorted objects (plexiglass cube and three buckets) suspended from a metal structure was intercepted by the beam, and sound waves were emitted that varied according to the different angles and speeds.


Sound production based on the movement of objects and the body.

Documents Consulted 

9 Evenings: Theatre and Engineering, Pontus Hultén and Frank Königsberg eds. ([New York]: Experiments in Art and Technology; The Foundation for Contemporary Performance Arts, [1966]) [12] p.

Manuscript, 1966 (1972-1973) : I Artists : B. Lucinda Childs, “Vehicle” / Harriet DeLong ; Julie Martin; Simone Whitman-Forti; Billy Klüver. Experiments in Art and Technology Records, 1966-1993, Research Library, The Getty Research Institute, Los Angeles, California (940003), Box 1, file 12.

Lucinda Chids, “Lucinda childs : a portfolio»,” Artforum, Vol. XI, no. 6 (Feb. 1973) p.50-56.

[Interview with Per Biorn / produced by the Daniel Langlois Foundation for Art, Science, and Technology; interviewers: Vincent Bonin, Éric Legendre, Julie Martin] (Shot the 25 of August, 2004), 4 videocassettes (3 hr., 45 min.): master, col., sound, Mini-DV. Interview made the 25 of August, 2004 in Berkeley Heights (N.J. USA). VID 00031593 / M.

“Projects for Stockholm Festival,” E.A.T. News, vol. 1, no. 2 (June 1, 1967), p.12-18.

“Art and Science: Two Worlds Merge,” Bell Telephone Magazine, vol. 46, no. 6 (Nov./Dec. 1967) p.12-19.

Vincent Bonin © 2006 FDL

(1) “Projects for Stockholm Festival,” E.A.T. News, vol. 1, no. 2 (June 1, 1967) p.12.

(2) “Art and Science: Two Worlds Merge,” Bell Telephone Magazine, vol. 46, no. 6 (Nov/Dec. 1967) p.15-16.