ES 20: Engineering the Acoustical World

For this new course taught by my dissertation advisor, I put together this demonstration showing the mode shapes in a guitar body that result from different strings being plucked. I used a Polytec PSV-500 scanning laser Doppler vibrometer to measure the vibration profile throughout the guitar body. The vibrometer is equipped with a galvanometer, which allows it to measure the vibration of an entire surface if a repeatable vibration stimulus is provided. I used a small string plucking robot to provide that stimulus. Each time a string was plucked, the vibration velocity at a single point on the guitar body was measured. Over time, an entire mesh of points covering the entire guitar body can be measured and the measured mode shapes visualized.