Up to six and a half million teenagers in America struggle to hear whispered conversations or leaves rustling in the wind.
That's according to researchers in Boston, Massachusetts who say a growing number of 12 to 19 year olds have suffered slight hearing loss.
Doctors are putting the blame on MP3 players causing damage to the hearing of young people.
The study used data from a nationwide health survey.
It compared hearing loss in 3,000 teenagers from 1988-94 and then compared it with similar data from 2005-06.
The researchers say hearing loss has increased by 19% during that time, meaning one in five teenagers now has some sort of hearing damage.
Some experts say it means teenagers should turn down the volume on their MP3 players and listen for less time.
But there's no absolute proof that the apparent hearing loss is a direct result of MP3 players or earphones.
"Our hope is we can encourage people to be careful", said the study's senior author, Dr. Gary Curhan of Brigham and Women's Hospital in Boston.
Most of the hearing loss was "slight", defined as inability to hear at 16 to 24 decibels.
A teenager with slight hearing loss might not be able to hear a tap dripping or their partner whispering "good night."
Those with slight hearing loss "will hear all of the vowel sounds clearly, but might miss some of the consonant sounds" such as t, k and s, according to Doctor Curhan.
He added: "I think the evidence is out there that prolonged exposure to loud noise is likely to be harmful to hearing, but that doesn't mean kids can't listen to MP3 players".
Each new generation of teenagers has found new ways to listen to loud music.
Brian Fligor, an audiologist at Children's Hospital Boston, said: "Today's young people are listening longer, more than twice as long as previous generations".