Bowing to a digital sound.
In their experiment at a center in Paris for the scientific study of music, the researchers are simulating the way oscillations build up in a string because of a bow's ability to respond instantaneously to the strings's motion. "We are dealing with a feedback system that is purposely unstable," says Weinreich.
As a long wire vibrates back and forth, a sensor measures its velocity about 32,000 times every second. These data go to a computer, which looks up the postulated frictional force that a bow would apply to a string moving at each particular speed. The force is translated into an electric current that is sent through the wire. A small magnet at the wire's bowing point converts this current into a force on the wire, which then moves, and the process repeats itself.
By changing the tables stored in the computer, Weinreich and Causse can test different theories about the role friction plays in the interaction between a violin bow and a string. "I'm now getting a much better insight into what the old theories predicted," says Weinreich. "I hope to go beyond that soon."
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|Title Annotation:||computer used to study vibrations in violin strings|
|Date:||Mar 9, 1985|
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