Sometimes poor reception or low volume are not the only reasons why it is difficult to hear what people are saying during a cell phone conversation, according to researchers in the United States. The research, which will be presented at the Acoustical Society of America’s annual meeting in San Diego this week, suggests that cell phones have a tendency to cut out our voices’ most high-pitched ranges.
Those high frequency sounds actually convey a surprising level of information, according to Dr. Brian Monson of the University of Utah in Salt Lake City, whose research indicates that talking to people on cell phones may actually result in missing the full meaning of what they are saying. “The prevailing thought was that, because high frequencies are not as loud in the voice, that the brain must not pay much attention to them,” Monson, who is a speech and hearing scientist, admits. “If the brain is paying that much attention to high frequencies, there must be some kind of perceptual information there.”
The voice of a typical male measure around 100 hertz and the voice of a typical woman around 200 hertz, but voices also contain quieter overtones that have frequencies that can go as high as 20,000 hertz. While scientists have generally assumed those higher pitched noises are irrelevant, Monson suspected differently and says that our brains end up having to work harder to understand what is being said when it is heard over a limited bandwidth.