Cooling fans are vital to keep computers functioning — but who wouldn’t love to get rid of the noise? Scott Sommerfeldt, dean of the College of Physical and Mathematical Sciences, has found both enjoyment and success in researching the applications of active noise control to this area of computer technology.
The theory of active noise control indicates that an unwanted sound can be attenuated by emitting a second sound with an interfering wave pattern. Sounds can be canceled at either a particular point, such as in noise-canceling headphones, or at all points. This second approach, called global attenuation, relies upon getting the control speakers and microphones in the right location.
This is Sommerfeldt’s specialty. His involvement in researching active noise control dates back to the beginning of his PhD and his most recent work has been conducted with the BYU Acoustics Research Group. Working alongside fellow faculty member Kent Gee (who Sommerfeldt first partnered with when Gee was an undergraduate student), he has led a series of five publications on the applications of active noise control to fan noise in desktop computers.
Building upon their published findings from 2003 and 2004, Gee and Sommerfeldt involved graduate student Brian Monson in exploring how to make the active control system inside the computer more compressed and compact. A fourth publication, involving another graduate student, Connor Duke, improved the noise control performance by optimizing the location of the speakers around the fan.
These successful studies are now culminating in a fifth publication on active noise control. The research, published this past January in the Journal of the Acoustical Society of America, was led by Ben Shaffer, a recent MS graduate. Shaffer worked to experimentally verify the theory behind Gee and Sommerfeldt’s data. By making precise measurements and plotting the complex data, he was able to demonstrate that the near-field interference results matched that predicted by the theory. Shaffer said the challenging process was still a very rewarding journey.
“I can honestly say that it was exciting for me to sit down in the control room after each measurement set and look at the results,” he said. “I was verifying theoretical research for a physical phenomenon that had never been verified experimentally before, so every measurement was a discovery.”
BYU’s success in applying active noise control to desktop computers has now attracted the attention of Intel, a world-leader in technological advancements. This past September, Sommerfeldt was awarded a grant for $64, 370 that is allowing his team to explore the implementation of active noise control in notebook computers.
Shaffer’s own research and Sommerfeldt and Gee’s past publications played a key role in the development of this new technology. Along with the challenge of creating a device that will fit into a clearance of only a few millimeters, they must adapt the previous model to find the prime locations for the speakers and microphones.
“A laptop radiates differently,” Sommerfeldt said. “But once we’re successful in finding exactly how the sound radiates, we’ll hopefully be largely in business.”
Though the theory of active noise control has existed for over eighty years, today’s digital technology is turning it into a flourishing research field. In BYU’s acoustics lab, students and faculty have access to an anechoic chamber — just the thing needed to make this research possible.
“We have wonderful facilities, as good as any in the country,” Sommerfeldt said of the newly renovated lab.
It seems new findings and applications will continue to come from the Acoustics Research group at BYU. Despite keeping up a very demanding schedule as dean, Sommerfeldt looks forward to the future of his research here as he continues studying alongside the bright minds in the group.
“Frankly, the enthusiasm of my colleagues and my students keeps me going,” he said.