Engineering Bjork’s Gravity Harp

The list of materials for robotic instrument builder Andy Cavatorta’s new project includes, but is not limited to, Mongolian horse hair, dried wasps nests, and plenty of vacuum tubes. For Cavatorta, a Media Lab alum who recently designed a twenty-foot high Gravity Harp for Bjork, this is all part of the process of creating awe-inspiring robotic instruments.

“My parents were hippies and listened to a lot of psychedelic music,” he said, “It made it seem like music was this playground where anything was possible.” In Cambridge, he brought his experience as a computer programmer and robot-builder to Ensemble Robot, a musical group founded by composer Christine Southworth combining musicians and robotic instruments to create groundbreaking new music. With Ensemble Robot, Cavatorta discovered new “physical ways of playing and expressing [electronic] music” beyond the customary “laptop performances.” During this time, he designed and built the Whirly-Bot out of precisely tuned corrugated plastic tubes, an instrument he described as sounding like “either an angry chorus of angels or smelling an entire pack of magic markers.”


Cavatorta’s big break came when Bjork and the filmmaker Michel Gondry came to the Media Lab one day. “People were lined up outside the conference room but didn’t know they were hiring,” he recalled. His designs would eventually become part of Bjork’s nature-themed album Biophilia, a multimedia production involving an album, a suite of iPad apps, custom instruments, educational workshops for kids, and a live tour. After a process of trial and error as the shape and scope of the project shifted, the Gravity Harp was born: four unique three-meter-long pendulums with a cylindrical harp on the end. In this instrument, the force of gravity is used to set and synchronize the musical rhythms while computers control the sequence of notes.

In his lecture, Cavatorta spoke with humor and candor about the process of realizing these “multidimensional, high-speed projects,” a journey in turns joyous and frustrating. The work by necessity involves a high level of collaboration — and more than a few “raging all-nighters” — between designers, musicians, and engineers as these musical creations evolve from the drawing board to the stage, from PVC pipe-and-cardboard mock-ups to massive but graceful mechanisms of fiberglass, walnut, and spruce. Despite the occasional setback, Cavatorta enjoys bringing something interesting into the world that was not there before. “I want to reach into the unformed future,” he said in an interview on Wednesday, stretching his hands forward as if to pull a new idea out of the empty air.

Posted on May 15, 2013 by Anya Ventura