Why cell phone conversations are hard to grasp

Updated: Oct 29, 2011, 19:00 PM IST

Washington: A new study has found that cell phones cut off the highest-pitched ranges of our voices that convey a surprising amount of information, making it hard for others to hear us.

This is might be one factor other than volume or poor reception that lead to frustrating cell phone conversations on a bus or in a bar, according to the study.

The results suggested that we might be missing the full meaning of what people say when we talk to them on our mobile devices.

“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,” Discovery News quoted Brian Monson, a speech and hearing scientist at the University of Utah, Salt Lake City, as saying.

“If the brain is paying that much attention to high frequencies, there must be some kind of perceptual information there,” he stated.

Unlike a monotonic sound like a whistle, voices also contain quieter overtones with frequencies that range as high as 20,000 Hz. But because most of the energy in our voices falls below 5,000 Hz, scientists have long assumed that those high-pitched sounds are irrelevant.

But Monson noticed that singers improved the quality of their voices by making adjustments in very high frequency overtones.

In a follow-up project, he found that people could detect tiny differences in the volume of high-frequency sounds – on the scale of just a few decibels.

“If they can understand what’s being said, that means there’s an ability to extract intelligible information from high frequencies, and nobody would have predicted that,” Monson said.

“If you’re in a situation where there’s low-frequency noise covering all of the information you’re used to getting from a voice, as long as you have the high-frequency stuff, you can still figure out what the person is saying and get the information you need,” he added.

The finding will be presented at the annual meeting of the Acoustical Society of America in San Diego.

ANI