AEROSPACE ENGINEERS MAY have discovered a way to use high technology to "tune" inexpensive guitars and other string instruments so they sound much better. It all started when Steven F. Griffin, who is studying for his doctorate in aerospace engineering at the Georgia Institute of Technology and who strums a guitar to relax, started wondering why custom-made guitars tend to sound so much richer than their garden-variety cousins.
Using strategically placed sensors, Griffin found that a guitar's main sound stems from the primary vibrations of the upper plate, the part to which the bridge is attached. He found that the secondary vibrations generate the overtones that are especially pleasing to the ear. But many secondary vibrations get absorbed by the thick wood used in inexpensive guitars.
Griffin figured that technology could compensate for this damping. So he installed a small piezoelectric crystal on the upper plate, which converts a minute current from two 9-volt batteries into vibrations that help the upper plate generate the desired overtones. Next, Griffin plans to test the concept on other string instruments.