Going Deaf from Rock 'n' Roll

The young are not listening to their elders, and perhaps they never have. But now it develops that with many of them, the reason may be medical. The young aren't listening because they can't hear. Just as nagging parents have long suspected, otologists now report that youngsters are going deaf as a result of blasting their eardrums with electronically amplified rock 'n' roll.

The hearing specialists used to worry about loud noise as a cause of deafness only in industrial and military situations. They knew that eight hours of daily exposure, year in and year out, to the din of the proverbial boiler factory would eventually result in permanent, irreversible hearing loss. Riveters were particularly susceptible. Then they learned that the same thing happened to aviators. And after the advent of jets, the hazard applied to ground crews at airports and flight-deck personnel aboard aircraft carriers--hence the introduction of insulated, noise-absorbing plastic earmuffs.

Villain Amplifiers. From industrial and military experience, the experts set certain standards for safety. Any prolonged exposure to a noise level above 85 decibels will eventually result in a loss of hearing acuity for sounds in the frequency range most important for understanding human speech. This range is roughly from 256 cycles per second, the pitch of middle C, to about 2,000 c.p.s., or the C three octaves higher. Acuity is impaired even earlier for higher pitches, such as violin overtones.

In discotheques and rock-'n'-roll joints, the trouble is not so much in the instruments themselves, or even the sustained fortissimi or the close quarters. The blame goes to the electronic amplifiers. An old-fashioned oompah military band, playing a Sousa march in Central or Golden Gate Park, generated as much sound. But the sound was not amplified, and was dissipated in the open air. A trombonist sitting in front of a tuba player might be a bit deaf for an hour or so after a concert; then his hearing returned to normal. A microphone hooked up to a public-address system did not appreciably increase the hearing hazard. What did was multiple mikes and speakers, and the installation of internal mikes in such instruments as guitars and bouzoukia.

"With these," says Dr. Robert Feder, a Beverly Hills ear specialist, "everything is reamplified many times, and the noise becomes nearly intolerable." Dr. Victor Goodhill of Hollywood reports that sound levels in many rock-'n'-roll night clubs soar to 125 db. Dr. Charles P. Lebo of the University of California took measuring instruments into two San Francisco rock-'n'-roll joints, where the cacophony was produced mainly by amplified guitars and percussion instruments (see diagram). Throughout the audible-speech range, Lebo found that the sound intensity averaged over 100 db at virtually all frequencies. It rose to 119 db at peaks in the center of the hall.

What to Say? Individuals vary in their sensitivity to loud noise. Lebo estimates that 10% of the people in such a hall would show no effects, 80% would have their hearing threshold raised by five to 30 db, and 10% would suffer a 40-db impairment, at least temporarily. As for permanent damage, some might suffer it after a week or two of steady listening, while others could take it for a year.

The man who had the problem closest to home, and studied it there, was George T. Singleton, an ear, nose and throat man at the University of Florida. He noticed that when he picked up his teen-age daughter Marsha after a dance she couldn't hear what he said in the car on the way home. Singleton recruited a research team and tested the hearing often 14-year-old ninth-graders an hour before a dance. Then tne investigators went to the dance hall, and found the average sound intensity to be 106 to 108 db in the middle of the dance floor. Directly in front of the band it peaked to 120 db. The test crew had to move 40 feet outside the building before the level dropped to a safe but still uncomfortable 90 db.

After the dance, the kids' hearing was tested again. Despite the youthful resiliency of their inner ears, all had suffered at least temporary hearing impairment, with the average loss at about 11 db. One boy showed a 35-db loss. The greatest damage was in the high-frequency speech range, involving consonantal sounds, similar to the loss felt by oldsters who complain that "everybody mumbles nowadays."

Dr. James Jerger and his wife Susan, who is also his research assistant at the Houston Speech and Hearing Center, got similar results after testing the members of a five-man combo. One player had a 50-db temporary loss, and three had already suffered a slight but permanent loss, although none was older than 23.

Why do the youngsters immerse themselves in noise that is so uncomfortable to their elders? A Florida teenager explained: "The sounds embalm you. They numb you. You don't want to hear others talk. You don't want to talk. You don't know what to say to each other anyway." So why listen? And, eventually, how?

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