My older son did the exact same thing when he was in high school in the late 80s. He spent a lot of time under the headphones listening to Metallica, Megadeth and the like at volume so high you could hear it in other rooms when he had his door closed. He joined the Air Force in the early 90s and told me the hearing tests they would give him in the service showed that his hearing was normal. And maybe it was, but every time he was home on leave, he'd crank up the treble on my stereo and bass head.That tells me theremust have been at least some temporary loss.
A couple of years ago at the FDP somebody posted a link to an online hearing test. At my advanced age I could still hear the 19 Khz test tone. That surprised me since you read about hearing loss with age, and I was even more surprised my computer speakers put out anything audible at 19 Khz.
