Razor blades. Banjos. Lasers. The fastest camera you’ve ever seen. One of the most intriguing labs at Rollins is attracting eyes and ears from around the globe.
Thomas Moore (Photo by Scott Cook)
In the basement of the Bush Science Center is an operating room for musical instruments. Oh, let’s just say it: The instruments are destroyed down here. Singing bowls from Nepal. Once-jubilant banjos from Dixie. A slit-log drum from Nigeria that is now a slit-apart slit-log drum.
“We’re especially hard on pianos,” says Professor of Physics Thomas Moore.
It isn’t that Moore’s students want to ruin beautiful instruments, but to find physical problems associated with acoustics they often need to dissect them to measure how factors like density and force affect sound. And they do it here, in a lab that’s gaining international acclaim. This latest iteration of Moore’s anechoic chamber was completed in 2013, the same year he was named Florida Professor of the Year for engaging undergraduate students in the micro-niche field of musical acoustical phenomena. As a leading participant in Rollins’ Student-Faculty Collaborative Scholarship Program, Moore has used this cave of discovery to inspire an unheard-of 25 students to produce published research.
“We were the first learning institution with a lab like this,” Moore says.
To his knowledge, one other has been designed in Vienna, Austria, and it’s a knockoff of this one at Rollins. Moore closes the door and turns out the light. His voice dies at your ear. A cymbal sits still, poised for an operation.
The ideal location for an acoustical lab is about 1,000 feet above ground where the room’s attributes (including echoes) are taken out of the equation. The next best place Moore could find was here: a controllable 18-foot by 18-foot space that he designed to be anechoic.
Those are high-density acoustic tiles on the walls. Sound-pressure waves bounce back and forth between the cones until they vanish, leaving only the instrument’s movements for the student-researcher to see. “Building it isn’t that dificult,” Moore says. “Building it well and using it well—that’s the difference.”
Prior to his chance encounter with a trumpet in 2000, Moore’s expertise was laser physics. That trumpet provided a natural marriage between laser optics and acoustical physics. In the lab, the laser illuminates the surface of the instrument being studied so its movements can be captured in micro-sequence.
Laser light, like sound waves, will reflect. Worse, laser light can burn or blind a person. Students use beam blocks made of stacks of about 100 razor blades to absorb the laser light. “It’s the same concept as the foam cones,” Moore says. “The light rays bounce between the blades and won’t reflect back.”
The electronic speckle-pattern interferometer (ESPI) splits the laser light into two beams, which are used to create a contour map of the instrument’s motion in a computer. An ESPI is a pricey piece of equipment, unless you can build or rebuild one yourself, which is exactly what Moore’s students do.
Ultra-high speed camera
To “see” acoustical nuances, you need a special eye. Enter an $80,000 camera capable of shooting 200,000 frames per second. With the help of the laser and interferometer, the camera captures instrument movements as minute as a fraction of the diameter of a human hair. The imagery also reveals stunning craftsmanship. “The steel pan is built with basic materials and we’re years away from figuring it out,” Moore says. “But we’ll keep trying.”