Link between orchestra instruments and hearing loss studied
DENTON (UNT), Texas -- After listening to an hour or more of crashing drums and amplified electric guitars, it's no wonder that concertgoers sometimes return home with ringing ears.Two University of North Texas professors, however, believe instruments other than those used in loud rock music can damage hearing. With help from students and faculty in UNT's College of Music, Drs. Kris Chesky and Miriam Henoch will determine the levels at which certain symphony orchestra instruments could be damaging.Approximately 25 students will play their instruments in piano (soft), mezzo-forte (medium) and forte (loud) scales in various keys, with the professors measuring the decibel levels of sound generated in the ear canal. Vocal students will also sing the scales. "The primary hearing damage among symphony musicians may come not from their own instruments, but from those of others playing near them," says Henoch, associate professor of speech and hearing sciences. "It has been proven that violinists have more hearing loss in their left ears than in their right ears because of the way they hold their instruments. The left ear is more exposed to the sound of the musician's own instrument."Under requirements from the Occupational Safety and Health Administration, employees should not be consistently exposed to more than 90 decibels of sound during the workday without wearing ear protection."The problem is that these standards reflect a typical eight-hour workday," says Chesky, assistant professor of music. "If musicians played for eight hours a day in a symphony hall, there would be no problem measuring the levels of decibels that they are exposed to, but musicians don't work eight straight hours. They usually rehearse in three- to four-hour timeframes and may practice on their own for more hours. Therefore, it's hard to measure how many decibels they are exposed to during the day." Henoch points out that a symphony such as Wagner's The Ring of the Nibelungen exceeds 110 decibels at some points.In addition, the shape of the ear canal amplifies and increases sound levels in the inner ear, where permanent damage can occur due to excessive sound levels, Chesky says."The sound that lines up with the resonant factor of the ear canal can be increased by 20 decibels," he says.Chesky says instruments with the most dynamic range produce higher decibel levels. Sound generated by a violin, for example, may exceed 100 decibels, while sound generated by double bass does not reach 85.In addition to permanent hearing loss, Henoch says musicians are at risk for other hearing disorders. "Some may develop diplacusis, which is a distortion in the sensation of pitch," she says. In recent years, nationally known musicians, including former Who performer Peter Townsend, have led campaigns to warn their peers of noise-induced hearing loss and urge them to wear earplugs, Henoch says."Some musicians may not want to wear them because they are afraid they won't be able to hear what they are playing," she says. "But musicians' earplugs today are made in such a way that you can still hear everything -- only at a much softer level."