They look like just another three-piece band, with drums, violin and guitar. But stop and listen to Edgar Berdahl and his colleagues, and you’ll notice things aren’t quite what they seem. Strange tones emerge from their instruments, sometimes without any of the performers moving, as an abstract soundscape washes over you.
The Haptic Drum, Overtone Fiddle and Feedback Resonance Guitar are all examples of what Berdahl, who researches technology in music at Stanford University in California, calls actuated instruments.
Berdahl and his colleagues have modified traditional instruments by adding electromagnets and other sensors that can both detect and induce vibrations, blurring the line between physical and computer-generated sounds. The instruments can essentially play themselves, while also allowing a person to control them. This allows very different sounds to be created. “The manner in which the external energy is injected into the instrument enables and even compels the performer to interact in new ways,” says Berdahl.
Take the Overtone Fiddle, created by Dan Overholt at Aalborg University, Denmark. It can be played like a regular violin, but signals can also be pumped directly into the instrument’s body, causing it to resonate and produce a wider variety of sounds. An iPod Touch controls the signals, allowing the performer to modify effects on the fly, while a bow fitted with a position sensor provides another form of input that can be used to modify the sounds.
The Feedback Resonance Guitar follows a similar construction, using electromagnets to vibrate each of the instrument’s six strings at a variety of frequencies. Notes can be artificially sustained, and the guitar can also play traditional rock “feedback” tones without the usual corresponding rise in volume – handy if you want to avoid blowing your amp.