By Daniel Shearer
Princeton Packet Staff Writer
Wednesday, March 31, 1999

   An ominous tone sounds. The noise grows, modulates and then diminishes, replaced by the resonance of metal bending under immense strain — a heavy pseudo-industrial wail. From this texture emerges a watery moan, almost organic, similar to whale song.
   It fits the dictionary definition of music — arguably, it is an expressive combination of tones — but the sound of Interface, created by two die-hard technology junkies, heads into a realm of its own. For comparative purposes, if normal music comes from Earth, this stuff is straight from planet Zed, where the space-time continuum has been severely disrupted.
   Accompanied by a computer-generated interactive video display, Interface will perform a free concert at Princeton University's Taplin Auditorium on April 3. The show will also include an interactive dance by Tomie Huhn, who will make sounds as she moves with several different kinds of sensors attached to her body, as well as a performance from Princeton University professor Steve Mackey on electric guitar.
   "We get up, we have no score, we have no notes," Mr. Trueman says. "What we have are fairly involved software and hardware instruments that we've built in a kind of improvisational sensibility. For some people, that makes us interesting. For other people, that makes us irritating."
   A few years ago, Curtis Bahn and Dan Trueman, doctoral students at Princeton University's music department, decided to connect an electric upright bass and an electric violin to just about every electronic bell and whistle allowable by modern technology. After years of development, their musical inventions — among them, a violin bow with four different kinds of computerized sensors — continue to push the boundaries of how musicians interact with technology.
   "I guess we call it free electronic improvisation," says Mr. Trueman, standing in a small room littered with computer gear. He's working on a doctorate in music composition at Princeton. Mr. Bahn plays a five-string bass, which detects changes in light, motion, touch and tilt, while Mr. Trueman performs using a six-string, "computer-extended" violin.
   "We started by just improvising together, playing acoustically and both of us were interested in seeing how technology could change and enhance the way we played together," he says. "We began using commercially available rack-mount hardware, samplers, looping devices, and eventually started using computers because there's a lot more you can do with them than with some kind of pre-fab factory unit."
   At first glance, Mr. Trueman's sound equipment looks just like the gear used by the average guitar player. Tucked on the bottom shelf of his rack, however, sits a Macintosh G-3 computer, which Mr. Trueman links through a digital connection to R-Bow, his custom designed and self-constructed violin bow.
   "Real engineers laugh at this," he says. "It's not a big deal, but for musicians, this is a lot to do. I've had to do a lot of programming here to get it to do what I want.
   "There's more time than I would like spent hacking on these things, but if you're going to get somewhere musically, sometimes you've got to build your own stuff to get there. You're not going to find these things in a store."
   Computerized violin bows, says Mr. Trueman, are not a brand new idea. The concept appeared in the 1980s, but aside from a few eccentric performers who fiddled around with the idea, the concept hasn't really caught on.
   "I demo this at computer music conferences, and it's a new thing that people are interested in," he says. "It's not mainstream at all. It's not even marketable. If I could market this then maybe I could make some money selling them, but the interest in these kinds of things currently is pretty limited, mostly because people don't know what you can do."
   The R-Bow, more formally known as the Trueman-Cook R-Bow, has a rather unwieldy looking variety of rainbow colored wires hooked up to two accelerometers that detect the pitch and position of the bow. It's the product of a collaborative effort between Mr. Trueman and Princeton University computer science professor Perry Cook. Dan points out that his name comes first in the device's title because he's the one who actually has to play what he calls "the Frankenstein."
   Two other sensors detect pressure — the amount of force the bow encounters as it moves across the violin. The guts of the bow, however, are contained in the palm-sized "violin bow computer" that Mr. Trueman clips to his waist when he performs. This little package of electronic wizardry is made possible by a "basic stamp" computer the size of a few credit cards.
   "This computer runs at 20 megahertz, and you can program it very easily from a DOS machine or a Windows machine, just by plugging it into the port," he says. "This little belt computer cost about $40, and it's got six different programs so the bow can behave in different ways."
   All of this "fancy stuff," as Mr. Trueman puts it, means the bow also can be hooked up to a state-of-the-art "physical modeling synthesis" program, which runs through his Mac computer. Mr. Cook was one of the pioneers of this idea, which models the sounds produced by the computer on the physical properties of each instrument. The computer's flute sound, for example, can be modified to control factors like breath pressure on the instrument and can even reproduce sounds that take into account the angle of the air stream going into the instrument.
   "I've taken these algorithms from kind of a research environment to a performance environment," he says. "Now there are a lot of people doing this, mind you, but it works for my purposes."
   Physical modeling works wonders on an R-Bow. Each of its sensors can be programmed to control a different sound property — vibrato can change along with the bow's position, and even extremely subtle sound properties, like the breathy oscillation that occurs right before a flute sounds, can be linked to bow pressure.
   "I can play the flute and the electric guitar, just about anything, simultaneously with my bow, which is kind of a trip," he says. "The Mac is doing that synthesis, in real time. Even just two years ago, you couldn't really do this on an affordable machine. You'd have to send it, tell it to do something, and then wait a few minutes and come back and listen to it.
   "You couldn't really use it in performance. Now, the machines are so fast that the time difference between when I gesture and something comes out is below what we can perceive."
   This technological wizardry may sound heavenly to a computer buff, but without a good speaker system, all this fancy synthesis doesn't truly pay off for an audience. For the past several years, Mr. Trueman has also been experimenting with spherical speaker arrays that take advantage of a performance space's acoustic properties. One of his latest projects is a portable, robot-like speaker unit, aptly named "R-2."
   "It pretty much named itself," says Mr. Trueman, as he unpacks the system from its case. "It's just a salad bowl; these are wooden salad bowls from Ikea, all wired up.
   "The idea is that regular acoustic instruments, they radiate sound in all directions. It's not just one direction, like guitar amplifiers. With this, you get reflections off the walls, and the ceiling and the floor the same way an acoustic instrument would resonate. It actually sounds like it's in the room."
   R-2 isn't extremely powerful, but its 12 car-stereo speakers can be adjusted to provide acoustic properties similar to an actual instrument.
   "One of the neat things about these is that I can send different signals out of each speaker, so that I can actually model the sound after a real instrument," he says. "When you walk around a violin or a guitar, the quality of the sound varies a lot. I can duplicate that with these speakers. When I have it set up you can walk around and guess which way the virtual fiddler is facing."
   Much of the motivation for Mr. Trueman's work with Interface comes from a desire to explore new areas in music. He describes his research in terms of the old mountain climber's adage — because it's there.
   "I grew up playing with other people, chamber music and jazz and fiddle music, but never this way," he says. "Not that it's better or worse, but it's new and exciting to be in that place and to be making music that you couldn't have imagined making, even a couple of years ago.
   "There's a lot of hours where it just seems like it's a waste of time, but fairly often now, I'm just knocked by where we go musically."

   Interface will present an evening of live interactive electronic music and multi-media imagery at Taplin Auditorium, on the Princeton University Campus, April 3 at 8 p.m. Admission is free. For information, call (609) 258-4239.