Wednesday, April 25, 2007


A stringless violin is set to bring emotion and pathos to that most soulless of art forms: computerised music.

Electronic musicians like to play their instruments into a computer using a Musical Instrument Digital Interface (MIDI) system, which lets them record the notes and how loud they are played. Once that data has been recorded on a hard drive, it can be played back through any MIDI compatible electronic instrument.
Sounds good. Except it doesn't. Composers agree that music created in this way often sounds dead and unemotional, because the system cannot pick up all the complex qualities that give the sampled instrument its characteristic timbre. Another reason is that the composer is denied useful tactile feedback from the instrument while editing and manipulating the music on screen.
Enter Charles Nichols of Stanford University in California. A violinist who developed an interest in computer music, he became frustrated by current technology. Taking data directly from the strings of a normal violin didn't work, he says. Microphones or pickups couldn't translate the subtleties of the instrument's tone.
That's because key aspects of a violin's sound comes from the way it is bowed. So Nichols has developed a device that tells a computer everything about a bow's motion, allowing it to generate a more realistic, emotional sound.
Angle and pressure
"I wanted something that could use my violin skills with the computer," he says. His virtual bow lets the composer use a violin-like contraption that has no strings. The bow sits above where the strings on a normal violin would be. The bow's angle indicates which combinations of strings are being played, and the height gives the pressure on the strings.

Cables attach the bow to four motors with sensors that detect its direction, position and movement. The motors also provide force feedback, similar to the friction a player would experience if they moved a bow on real strings (see graphic).

The motors feed this information on the vertical, rotational, horizontal and longitudinal motion of the bow into a computer, which uses it to control any computer-synthesised instrument - such as a piano or harp - but with violin-style expression.

Obviously, real violins require you to finger the strings as well as bow them. Nichols plans to install a touch pad on the machine's neck so that the player can modify the lengths of the virtual strings and play the full gamut of notes. He will then put his money where his mouth is: he's planning a public performance later this year.

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