Since the Sydney Opera House opened over 50 years ago, countless musical stars, world leaders and awestruck patrons have visited its iconic halls.

The outside forecourt has been blanketed by thousands of bare bodies in the name of art and, inside, an only slightly less naked Arnold Schwarzenegger even won a body-building title. There have been renovations and controversies, protests staged and history made.

And the constant, through it all, is Terry Harper.

He’s been tuning the building’s pianos for half a century, working behind the scenes to make sure the uber-technical instruments are ready for the world’s best musicians.

It’s a family legacy started by his father when the Opera House first opened in 1973 – and one that ended this week, with Terry’s retirement.

The 69-year-old still remembers the first time he stepped into the half-finished Opera House, as a wide-eyed child.

“The sails were up, but it was all very bare,” he tells the BBC, gesturing to the edges of the grand Concert Hall.

“There was nothing inside… You could see out to the harbour on both sides.”

At the time, he had no inkling he’d spend most of his life inside the iconic venue. His dad, on the other hand, no doubt had grand plans, Terry says.

By then, Liverpool emigrant Ron Harper was renowned on the Sydney music scene as both a piano tuner and a performer.

“He would take me to these nightclubs as a [kid] in my little school uniform. And I would be seeing all of these world-class acts,” Terry recalls. He rattles off a list including Welsh songstress Dame Shirley Bassey, stage icon Liza Minelli, and British TV and music darling Cilla Black – whom they even drove home after her performance one night.

“It was an interesting childhood,” Terry surmises, with a chuckle.

But it’s one which instilled in him a love of music – even if he wasn’t particularly interested in making it himself.

Somewhat ironically, Terry admits he spent about a year learning piano before giving it up, dabbling with the drums and his school choir instead.

It was in 1973, shortly after the Opera House was officially opened by Queen Elizabeth II, that his father Ron got his fateful call-up.

“One day, the Sydney Symphony was rehearsing downstairs, and the piano hadn’t been tuned particularly well by whoever had been in in the morning,” Terry says. “One of the people working here knew my dad.”

Three years later, a 19-year-old Terry would join Ron under the sails, after completing a one-year piano tuning course when he left school.

He started on rehearsal pianos in the backroom, while building up his skills and confidence, before finally taking over when his dad retired a decade later.

These days, he can walk into a room and immediately know if the piano is out of tune.

“I always had a very good sense of pitch,” he says, “[but] it’s difficult to master.”

And it’s all done by ear.

Tinkling on the piano in front of him, he explains this one has 243 strings. For most of the keys, three separate steel wires combine to make the note.

“Once they start to deviate from the same frequency, they cause these things which we call beats, and that’s what we’re listening for when we’re tuning.”

“Can you hear this?” he asks, enthusiastically.

Alas, I – a music pleb – cannot.

“It’s not like tuning a guitar,” he says, offering me some solace.

The process can take up to 90 minutes, and each of the 30 pianos in the building need to be tuned basically every time they’re used.

“There’s so many strings in there that can wander out of tune, especially when you’re playing big piano concertos,” Terry explains.

“I refer to these as being F1 racing cars… They’re really gunning them.”

It can be a demanding and relentless job.

“It doesn’t stop. And it’s night times, it’s early mornings, it’s two and three times a day,” Terry says.

But the perks – which include brushing shoulders with some of the globe’s most-decorated musicians and easy access to the most sought-after tickets in town – aren’t to be scoffed at, he hastens to add.

Terry has also tuned pianos in many other notable locations – from the Royal Albert Hall and Abbey Road Studios to the BBC broadcast offices.

But none occupy a spot in his heart like the Opera House.

“For me, it’s a very happy place. It’s pretty much been my life.”

Earlier this year, after five decades, Terry decided it was time to hang up the tools.

“I got quite cozy during Covid, not having to work,” he quips.

His son couldn’t be tempted to take up the family business – “he’s into computer stuff, like all good young men are” – and so Friday also marked the end of the Harper legacy inside the Sydney Opera House.

The venue has opened a tender for a new contractor to tune their pianos – and Terry says he’s heard a rumour they could be replacing him with several tuners.

“I think somebody owes me some money… I’ve been doing the work of six people,” he teases.

Jokes aside, he admits that as his departure has crept closer, a wave of emotions came with it.

“Piano tuners, we’re fairly solitary,” he says. “We like to be in a room by ourselves with quiet, because you have to focus and listen to what you’re doing… [but] I’ve always had the camaraderie of all the people that work here.”

“I’m going to miss the place.”