Commissioned for SFMOMA’s 75th anniversary in 2010, this site-specific installation by San Francisco-based sound artist Bill Fontana translates the architectural space below the museum’s oculus skylight into a live, musical composition. Sonic Shadows reveals the musicality of building elements like the fifth-floor pedestrian truss bridge and boiler room pipes by transforming them into musical instruments.
This sound sculpture utilizes a network of eleven accelerometers (vibration sensors) to capture what are usually imperceptible movements in various building elements and then ensonifies the area around the footbridge using four ultrasonic speakers on pan-tilt heads and an eight-channel array of miniature loudspeakers.
The recording and processing of the accelerometer signals, as well as the movement of the DMX-controlled pan-tilt heads and playback through the loudspeakers, are all controlled via a computer running Max/MSP. All Max programming and system design were done by Arup in close collaboration with the artist.
All aspects of the piece--from input to processing to ouput, as well as overall system control--are controlled by Max/MSP. Specifically, output from the accelerometers is sent to Max/MSP through an ADC, and then processed/panned/mixed and sent to the two loudspeaker arrays through pan and gain sequences composed by the artist. The ultrasonic loudspeakers are panned/tilted through DMX commands, also sent by Max.