A group of researchers from the Southern Polytechnic State University (SPSU) in Marietta, Georgia, and the Georgia Institute of Technology (Georgia Tech) in Atlanta, investigated vuvuzelas’ acoustics and their potential impacts on hearing and will present their findings at the Acoustical Society of America’s upcoming 162nd annual meeting in San Diego, Calif., Oct. 31-Nov. 4, 2011.
What the researchers found is that the sound levels from single horns ranged from 90 to 105 decibels at the players’ ears. They also discovered that the horns’ impact is greatest when blown simultaneously with many others, such as at the World Cup, where the levels within an audience may well approach 120 decibels.
“For perspective, 100 decibels is the level of noise you’d hear at a rock concert. An ambulance siren or pneumatic jack hammer produce about the same level of noise as the vuvuzelas in a stadium, 120 decibels, which is at the threshold of feeling and produces a tickling sensation in your ears,” explains Richard Ruhala, associate professor and program director of mechanical engineering at SPSU. “The threshold of pain is 140 decibels. Sustained exposure to 120 decibels is 1,000 times the acoustic energy that causes hearing loss (with long-term exposure). That’s why OSHA [Occupational Safety and Health Administration] requires people working near those noise levels to wear hearing protection.”
Ruhala worked with his wife Laura Ruhala, also a researcher at SPSU, and Kenneth Cunefare, a professor of acoustics at Georgia Tech, to record the sound levels produced by a number of vuvuzelas, including one that had been used at the 2010 World Cup.
“On the field of play, with just a few percent of a stadium’s audience blowing vuvuzelas, the predicted levels could exceed 90 decibels, which is a level that would interfere with communication between players and impair their ability to hear the calls of officials,” points out Cunefare. “At the end of the day, though, the use of these horns at sporting events is maybe as much a cultural and participation choice as anything else. Perhaps there’s a product marketing opportunity here: Hearing protectors for sale at sporting venues in each teams’ colors?”
The researchers are continuing their work, analyzing the precision sound power and directivity of measurements already obtained. They’re also zeroing in on creating more accurate sound models to evaluate the sound pressure levels vuvuzelas produce in a stadium, thanks to the aid of Tina Ortkiese, an acoustic engineer.
The paper 5aNSb1, “Vuvuzelas and their impact,” will be presented Friday morning, Nov. 4.USEFUL LINKS:
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