"Certainly the risk of hearing damage is very real, particularly people who use these types of snug-fitting earphones where there's ambient noise, such as in the subways," said Dr. Christopher Linstrom, an ear doctor with the New York Eye and Ear Infirmary.

Because most earphones don't block out background noise, users tend to crank the volume. "If they're listening at a comfortable level to themselves, it's probably too loud," Linstrom said.

Robert Novak, director of clinical education in audiology at Purdue University in Indiana, said he's seeing too many young people with "older ears on younger bodies" - a trend that's been building since the debut of the Walkman.

"It's a different level of use than we've seen in the past," he said. "It's becoming more of a full-day listening experience, as opposed to just when you're jogging."

Novak and colleagues have been randomly examining students and have found growing incidence of hearing loss, including mild ear-ringing or trouble following conversations in noisy situations.

Hearing specialists say they're also seeing more people in their 30s and 40s - many of them among the first Walkman users - who suffer from more pronounced tinnitus, an internal ringing or even the sound of whooshing or buzzing in the ears.

Linstrom said in noisy situations, users should simply play their portable music players a little softer than they'd like.

By Derek Rose