When Eric Singer designs a musical robot, his primary goal is that it sound, well, musical. Even so, the electric guitar-like sounds that emanate from the GuitarBot -- his first and perhaps signature instrument -- elicit gasps from audiences.
"The first time you hear it, it's a surprise," he says. "The closest thing I could describe in the human world is having four people play one-stringed slide guitars exactly the way you tell them to."
The instrument consists of four independent units, each a metal plank with a single guitar string and a single magnetic pickup that amplifies the sound. At the bottom of each string is a standard guitar pick, each screwed onto a rotating base that brings the pick into contact with the string. Another device, meanwhile, controls the pitch of each note by sliding up and down the string, according to its program. When the robot runs at full tilt, the sliding pitches have a crazed intensity, zipping up and down the frame so quickly that the whole construct bobs and sways on its stand.
Rather than just making a robot that can manipulate a standard guitar, "as much as possible, we try to create our own instruments," Singer says. "It's more interesting to me to build a new kind of instrument that happens to be robotic."
The GuitarBot's chassis and most of the parts were machined by hand. The sliders that set the pitch make use of parts from a cabinetry drawer-slide; their movements are controlled by a device developed from an inkjet-printer mechanism, which uses a belt drive to quickly move to precise positions.
When programmed, the GuitarBot is capable of high speeds and extreme precision, and it can achieve intervals and sounds simply not possible for a human musician. While Singer can play a little self-taught guitar, "as a composer, I can sit down and write things that I can't possibly play, but that the GuitarBot can. It opens up new compositional worlds, and new interaction worlds."
On the other hand, despite its technical virtuosity -- and bad-ass presence -- the GuitarBot isn't terribly expressive. It sounds great on a chuggy metal riff, and contrapuntal movements work well, but getting it to really sing is another matter.
"There are plenty of things that the GuitarBot can play that Eddie Van Halen can't; there are plenty of things Eddie Van Halen can play that the GuitarBot can't," says Singer. "So you wouldn't want to replace one with the other. Better yet, you'd want to get them both onstage and see what happens -- have a shredding contest."
The original GuitarBot is now semi-retired in favor of GuitarBot 2, a more robust version. But if you're starting to fantasize about replacing a certain troublesome bandmate with a machine that will never have "creative differences," be warned that they are pricey.
"I would love to be able to make a GuitarBot for anyone who's interested in playing with one," Singer says. "But the fact is, it's five figures to build one of these and support the group and the artists that are involved in the process."