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Annie Jones
BYU physics professor Scott Sommerfeldt listens to one of four tiny speakers in the system he designed to suppress the noise from a cooling fan.

PROVO — Come on, feel the white noise.

If you do, Brigham Young University physics professor Scott Sommerfeldt says, things will actually get quieter.

"The sound waves are a little bit like numbers — when you add a negative two and a positive two, you get zero," Sommerfeldt said. "It's kind of like doing the same thing with sound."

Sommerfeldt, along with former BYU graduate student Kent Gee, is using a technology called "active noise control" to help quiet the humming that cooling fans in office equipment make by using opposing sounds to cancel out the noise.

Their work is getting national attention and will appear in the latest issue of the Noise Control Engineering Journal, which will be available Monday.

It may also pay off for the pair, who are in the process of patenting the cheap technology used to quiet office noises.

"We believe we've succeeded in creating a system design that not only works but is also cost-effective," Gee said. "Hopefully, that will lead to the development of quieter, yet affordable, products for the average consumer."

While equipment such as computers, copy machines and printers aren't very loud, Sommerfeldt said the sum total of the sounds can prove distracting when people are trying to concentrate at work.

Sommerfeldt said he noticed the problem when the noise from an overhead projector forced him to talk louder during a classroom lecture, leaving him with a sore throat.

Using expertise that Sommerfeldt honed while working with NASA on a project that sought to reduce the noise from turbofans in jet engines, he and Gee began to pit noise against noise to produce silence.

By using a four-speaker system that tightly surrounds the cooling fan, they were able to reduce the overall sound made by the fan to around 12 decibels.

"That's like going from soft talking to a low whisper," Sommerfeldt said. "That may not seem like much, but add that to other office equipment that's also making noise, and it can be distracting and fatiguing to your ears."

While it sounds ironic, the concept of fighting noise with noise works because sound travels through the air in waves of fluctuating pressure. When scientists apply an opposite wave of conflicting pressure, the original sound — like the hum of a cooling fan — nearly disappears.

However, ridding the air completely of unwanted noise is essentially impossible since the two sound waves must simultaneously arrive at the same spot to totally eliminate the original sound.

Still, the reduction in noise is enough to eliminate headaches.

"There's some sound left to it," Sommerfeldt said, "but if you hear it with the noise and then without, you hear a difference."

The cost of the BYU system, which includes speakers, cables, a sensor and a computer chip, is inexpensive at an estimated $20 — something that appeals to cooling fan manufacturers.

If the pair teams with manufacturers to market quieter fans, the sound of silence may also prove profitable for BYU.

"We're cautiously optimistic, but there is still some water to go under the bridge," Sommerfeldt said. "The hope is this technology could become a money-making venture for the university, but that's still in the future."


E-mail: lwarner@desnews.com