AceShowbiz - AC/DC star Brian Johnson fought to control his hearing loss with the help of monthly meetings with an ear expert who used the bone structure in his skull as a receiver.
The "Thunderstruck" singer was forced to step away from the band during the Rock or Bust tour in 2016 after doctors told him he was putting his hearing at risk if he continued.
AC/DC drafted Axl Rose as a replacement as Johnson headed home and started a long process of restoring his hearing.
"It was pretty serious," the rocker tells Rolling Stone. "I couldn't hear the tone of the guitars at all. It was a horrible kind of deafness."
A hearing specialist visited him once a month with a contraption he insisted would help Johnson at least get back in the studio.
"The first time he came down he brought this thing that looked like a car battery," Johnson explains. "I went, 'What in the hell is that?' He said, 'We're going to miniaturize it'. It took two and a half years. He came down once a month."
"We'd sit there and it was boring as s**t with all these wires and computer screens and noises. But it was well worth it."
Johnson kept his bandmates up to date with his progress and, when AC/DC founder Angus Young decided it was time to regroup for a new album, the singer was raring to go.
"It was with the boys in full battlefield conditions and it was smashing, brilliant," Johnson adds. "I felt like I was a kid again."
He wasn't the only band member coming back from a debilitating condition - bassist Cliff Williams' battle with vertigo prompted him to retire from music after the "Rock or Bust" trek.
"I had stuff going on while I was on the road, terrible vertigo," he says. "For me, I just thought that it was my time... (Now I'm) a changed animal. I feel in my gut it's the right thing."
Williams, Johnson, and drummer Phil Rudd quietly returned for recording sessions in early 2019, and were spotted together in Vancouver, Canada.
The bass player admits Johnson and Rudd's return convinced him to come out of retirement, "It was like the old band back together," he says. "It was not like starting over again, but as close to the band that's been together for 40-plus years as we can possibly make it. I didn't want to miss that."
AC/DC recently confirmed their comeback with the announcement of a new album, reportedly titled "Power Up".