AC/DC were forced to postpone the remainder of their 2016 tour due to singer Brian Johnson’s risk of “total hearing loss.” This isn't the first time that a rock 'n' roll star has dealt with this issue.

Some musicians, like Paul Stanley of Kiss and the Beach BoysBrian Wilson, have struggled with hearing problems their entire lives. Stanley was born with Grade III microtia in his right ear, a congenital disease in which the external ear is underdeveloped, causing deafness. Wilson has also been unable to use his right ear since childhood, and it’s undetermined if he was born with a degenerative condition or if it was the result of his father’s physical abuse.

But what about hearing loss caused by a lifetime of exposure to sound at high volumes? Dr. Carol Rousseau, a clinical audiologist, tells Ultimate Classic Rock that “music-induced hearing loss is caused by damage to the hair cells in the cochlea or inner ear. Hearing loss can occur gradually over time or, if it's loud enough, it can occur after just a single exposure. You can have a temporary threshold shift, where the hearing can return after approximately 16 or so hours after initial exposure. But after multiple exposures — like playing concerts night-after-night — and not letting your ears rest, it can lead to a permanent threshold shift.”

Rousseau says that National Institute for Occupational Safety and Health (NIOSH) “considers a safe noise dose to be 85 decibels (dB) for eight hours a day,” but that for every three-dB increase, that time period is cut in half. And for bands that regularly pack bigger venues like arenas and stadiums, that can prove costly down the line. “I’ve read the loudness levels at AC/DC concerts range anywhere from 105 to 130 dB,” she notes. “At 105 dB, damage can occur after only about 15 minutes of exposure. And damage to the inner ear can occur instantaneous at 120 dBs. ... It’s balancing loudness and duration.”

AC/DC probably understand the importance of that balance. Johnson believes that his hearing problems came as a result of forgetting to put in earplugs before participating in a car race, not from performing music. In 2008, his bandmate Angus Young said that his own hearing is a “thing I have never had a problem with. It is also a very good reason that I am running around a lot.”

While hyperacusis (an increased sensitivity to volume) or diplacusis (difficulties in pitch perception) are conditions that can occur as a result of prolonged exposure to loud music, the most common type of hearing damage suffered by musicians is tinnitus, where the ear perceives sound, often in the form of ringing, even when none is present. While there’s no cure for tinnitus, it can be treated, most commonly by having music or a television playing in the background to “mask” the ringing. Many hearing aids now have built-in maskers that have proven effective.

Pete Townshend of the Who has suffered from tinnitus since at least the mid-‘70s. There’s a scene in the 1979 documentary The Kids Are Alright where Townshend tells Keith Moon that, after getting his ears checked, the doctor had advised him to “learn to lip read.” On the band's 1989 reunion tour, Townshend dealt with his hearing problems by playing acoustic guitar behind a glass partition for the majority of the set. In 2012, he was forced to leave the stage because the onstage volume was too loud.

Townshend and Johnson are far from the only classic rockers who have encountered some hearing damage throughout their careers. Sting, Eric Clapton, Neil Young, Jeff Beck and Ozzy Osbourne are among the many stars who have gone public with their hearing problems.

Watch Lars Ulrich Talk About Hearing Damage

Metallica drummer Lars Ulrich has had tinnitus for virtually all of his professional career. By 1988, it had started to become unnerving. “I would fall asleep often with the television on, and I would wake up in the middle of the night to go turn the TV off," he told CNN. "Except it wasn't actually on. When I realized that I was doing that frequently, actually getting up to turn the TV off that was not on to begin with, I realized that maybe I had some issues."

"My left ear is only there for aesthetic purposes,” Ted Nugent revealed in USA Today. “It just balances my head so I don’t fall over. I’ve played over 5,000 concerts and have subjected myself via my cravings to massive sonic punishment. My left ear is beat to hell. ... I’ve worn a plug in my right ear since 1965, and I am a living scientific experiment, because I can hear fine out of my right ear even though I play outrageously loud sonic configurations by creating feedback. I have to stand directly in front of the speaker, so I live in the eye of the storm."

Ironically, a device intended to help musicians hear better onstage is one of the unwitting causes of hearing loss. "One of the major sources of loudness is when each musician has a floor wedge monitor," Rousseau says, "and each musician is fighting to hear their own monitor over their bandmates'."

In 1995, Alex Van Halen, who has "lost 60 percent hearing in [his] left ear and 30 percent in [his] right," asked Van Halen's soundman, Jerry Harvey, to come up with a solution to the dilemma caused by wedge monitors. Harvey created a custom-fitted earpiece that connected wirelessly to the monitor soundboard that allowed Van Halen to not only hear his mix more clearly, but at a lower volume too. "I absolutely wish these things had been around in the beginning, because you don't get dizzy or noise drunk," Van Halen told Inc..

After other artists got wind of the device, Harvey founded Ultimate Ears, and many audio companies started creating their own versions of in-ear monitors (IEM) in the wake of its success. In 2008, Ultimate Ears was acquired by Logitech for $34 million.

Rousseau notes that other health factors -- such as diabetes, high blood pressure or smoking -- can heighten the effects of noise on hearing loss. And even though modern technology has made it possible for musicians to protect their ears better now than in rock's early days, it's important for them, and fans, to be smarter when it comes to volume, because hearing loss is irreversible.

"If you get a scratch on your nose, in a week that'll be gone," Ulrich said. "When you scratch your hearing or damage your hearing, it doesn't come back. I try to point out to younger kids ... once your hearing is gone, it's gone, and there's no real remedy."

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