BYU researchers use physics to study the sound of music

Posted at 10:06 PM, Aug 09, 2015

PROVO, Utah -- If you stand on one side of a musical instrument it sounds one way, but stand on the other side and it sounds a little different.

There is a fascinating science behind the physics of music, and research at Brigham Young University is exploring that science.

Judy Garland as Dorothy singing "Over the Rainbow" in the 1939 film "The Wizard of Oz" is one of the greatest songs ever recorded.

It’s a timeless classic, but Kyle Miller is sick of it. That’s because Miller plays that clip over and over.

"You have to be really patient and sit in the same spot for about three hours," he said.

Miller just graduated from BYU with a bachelor’s degree in physics and a minor in music.

The money is good, he says, plus it combines two of his skills.

"I play the saxophone with 'BYU Synthesis,' the jazz band, but I also was interested in acoustics because, as a physics major and interested in music, acoustics is the study of sound--so it kind of blends both,” he said.

He’s part of a research project that studies the directivity of musical instruments and how they radiate sound. The work is done in a special chamber lined with anechoic wedges.

The musician plays the clip, is rotated five-degrees, and then plays the clip again.

"Then we rotate them another five degrees, and they repeat it again, and they do this over and over again until we've swept out a full sphere of data,” said Tim Leishman, an associate professor of physics at BYU. “So they have to repeat their scales, or their musical excerpt, 72 times."

A laser attached to the instrument is kept aligned with a target to keep it on the right level. The process gives researchers more than 2,500 channels of data on radiation patterns.

Those patterns are then used in computer models, and the research is useful to musicians, recording engineers, or to those designing concert halls and other performance venues.

The ultimate goal is to make music better around the world.

“Not only here at BYU, but the abilities of other researchers around the world in improving musical performance venues,” Leisman said.

The next step for the BYU researchers is to put the microphones closer to the instrument while using a method known as "near field acoustic holography" to project the data outward or inward rather than having it scanned at one fixed distance.