A new study by a University of Colorado at Boulder researcher and a Boston audiologist reveals that consistently listening to an iPod or MP3 player at the highest volume levels - even if just for a few minutes a day - can cause long-term hearing damage.
It would take only 5 minutes a day of listening to an iPod full-blast to cause hearing damage, according to the study, conducted by CU Ph.D. student Cory Portnuff and Brian Fligor, a doctor at Children's Hospital Boston.
While the concern about too-loud music players has existed for years - going back to the days of the Sony Walkman - Portnuff and Fligor's study is the first iPod Study to read the study on optimal audio levels for preventing hearing loss.
The two are scheduled to present the results of their study Thursday at a National Hearing Conservation Association conference in Covington, Ky.
Portnuff said the popularity of iPods and other MP3 players drew his attention. "I did notice that students, in my opinion, are carrying portable electronics more often now," he said. "And as there was no research in this field, I decided to undertake this."
The study used a microphone to record volume outputs from six kinds of MP3 players and five kinds of earphones. Using a computer, the researchers then compared those outputs to already existing safety standards on noise levels that cause hearing loss when using industrial equipment.
All the MP3 players, regardless of whether they blasted heavy metal or smooth R&B, were capable of producing 100 decibels or more at full volume. That's the equivalent of having a running chainsaw next to you or being at a loud rock concert, Portnuff said.
At full volume and for all earphones, listeners have only a few minutes a day before facing damage. Portnuff said the actual hearing damage people receive could vary based on whether they have a "tough" ear or a "tender" ear. "People are putting themselves at risk by listening to these devices at high levels," he said.
Concern about MP3-related hearing loss has grown in recent years. Hospitals have put out warnings about the danger. Earlier this year, a Louisiana man sued Apple, the maker of the iPod, saying the company didn't do enough to warn users about the risk of hearing loss.
The company has sold 67 million iPods, the most popular MP3 player on the market, since introducing the gadget five years ago. Apple spokesman Tom Neumayr on Wednesday declined to comment on Portnuff and Fligor's research. He did, however, point to a website - apple.com/sound - that provides details on iPod volume- control software and warning about the danger of listening to music too loudly.
Fligor said he has begun to notice incidents at his hospital in which kids have a slight hearing loss, and the only explanation seems to be an overuse of a music player. "It literally takes 10 years before this shows up," he said. "So the fact I see it at all is concerning." Sue Dreith, manager of audiology services at Children's Hospital in Denver, said she hasn't seen any cases of music-related hearing loss in her patients. But she said that doesn't mean the concern isn't real. "Noise can be damaging to the hearing," she said. "I think it's really important for parents and professionals and school districts to educate about noise exposure and the potential damage to hearing."