Grammy nominations? He and older brothers Isaac and Taylor can claim three.

Studio albums? Try six, starting with their major label debut Middle of Nowhere featuring breakthrough singles Mmmbop and Where’s The Love.

Establish their own independent label? 3CG Records, in 2003.

Celebrate a quarter century as a band? With no less than a 60-date world tour.

Zac, 33, says the often-underestimated pop-rock trio from Tulsa is unashamed to set their sights on lofty goals.

It’s why they’re finding themselves with 50-strong symphony orchestras on stages at revered US venues including New York City’s Beacon Theatre and Los Angeles’ Greek Theatre.

They’ve collaborated with Oscar winning arranger, composer and conductor (and musician Beck’s father), David Campbell, to re-imagine some of their best known material and seven never-released-to-the-public songs, plus debut four brand new creations.​

Side by side, the songs weave a story about aspiration and fortitude against the odds.

The result, String Theory – both a world tour and a 23-track double album featuring a Prague-based orchestra – is undoubtedly their most ambitious musical project to date.

“We tend to be very focused on the next album, the next project, the next thing,” Zac tells the Newcastle Herald, in between performances in Chicago and St Louis.

“We wanted to do something [last year] to encapsulate the 25 year mark as a band and so we did a greatest hits sort of tour and put together a compilation of songs.

“But that wasn’t a new album, it didn’t have all that release of writing and recording a big new record and so that energy was still there.

“This [String Theory project] sounded exciting and hard and in a way mysterious, because you don’t know how to approach starting – who to talk to, how do we find the orchestra and so on and so forth – so that excitement of the biggest mountain we could think of became a real driving force for it.

“It’s really interesting to hear your own music, to try and reinvent it, capturing obviously what you love and what’s core about the songs, reinventing the arrangements and making them more lush and filling them out.

“Just the weight that can be added to what you’re saying.

“The songs become deeply associated with a totally different story and they have new touch points.

“We want people to take the opportunity to listen to the [seated] show almost like you listen to an album, to be very present in that experience.

“There’s moments for clapping and singing, there’s a place for standing and dancing, but it builds.

“You’ll hear it, you’ll feel it, if you’re listening, what time that is.”

The tour lands in Australia in February next year.

The schedule doesn’t yet include the Hunter, where local fans have a rolling Bring Hanson to Newcastle campaign. 

“If I could simply go where I wanted to go, then we would go play Newcastle every time,” Zac says, “that’s something we want to happen”.

But it does feature two shows at the Sydney Opera House on March 4 and 5. The first has sold out.

“I remember touring the building on our first trip to Australia [in 1997] and standing on stage and singing in that room and thinking how special it would be to do a show there,” he says.

The band will meet with a new conductor and play with a different orchestra on each of its six Australian dates, which straddle two non-symphony shows at Melbourne Zoo.

“We play the whole show with every orchestra that morning so we’ve been through everything before the actual performance.

“That makes it much more labour intensive, to be singing and playing the whole show twice a day.

“It’s almost like prep for Broadway. Maybe that’s our next project – Zachary’s Technicolour Dreamcoat?”

Jokes aside, he says, the hours of groundwork have been far from the project’s biggest challenge.

That title goes to finessing String Theory’s narrative arc, which he says illustrates the band’s ideology.

“Simply picking the songs for the purpose of telling a story was probably the biggest hurdle, because when people hear you’re doing a symphony tour there are a lot of different expectations and you have to put all of that to one side,” Zac says.

“It’s [the setlist and tracklist] not… the logical choice for what everyone wants to hear, from a fan point of view.”

Not that members of the band’s rusted-on following are complaining. Many have been anticipating this project for more than a year and are upholding what has become, in these circles, the celebrated and in some cases routine ritual of flying from the opposite side of the globe to catch multiple performances.

They speak of feeling “proud” after seeing String Theory, which is split in halves and includes the reworking of songs such as rousing latest single I Was Born and the contagious No Rest For The Weary, but omits favourites such as Penny and Me and assumed front runners  Underneath and I Will Come To You.

Related: Hanson eye Newcastle show 20 years after Mmmbop

“We used the lyrics of the songs as the driving force,” Zac says.

“All the words, all the stories these songs tell, they connect.

“It was the Hanson ethos encapsulated in a show, almost musical-esque but without the choreographed dancing.”

The thread running through their back catalogue is optimism and persistence despite struggle and the reminder that a dream, however improbable, is worth the fight.

“Even last year, I Was Born, it’s about trying to tell people to recognise that power they have as an individual to achieve amazing things if they put themselves through it: the potential that everybody has.”

Fittingly, Zac says, String Theory has bolstered the trio’s confidence.

“Before this process I thought ‘Well they’re the good musicians and we’re the street musicians,” he says.

 “It’s really like they’re acrobats and we’re magicians.

“The classical world and the band rock and roll world, they’re cut from different cloths.

“There’s also a certain showmanship and a certain presence that is not there in the classical world, that engagement of the audience.

“You’re trying to bring the best of those two things together.”

Related: Hanson – 22 years on from the boy band, still going strong

He says the band’s relationship with fans is built on fostering an experience, stoking connections and taking them behind the curtain.

They offer fanclub members additional resources to explore their work, plus direct access to themselves, through annual Back to the Island concert events in Jamaica and Hanson Day celebrations in Tulsa.

As for the band’s next challenge, Zac says they won’t be taking the easy route.

“What would it sound like if we did our version of a Billy Joel record or a Led Zeppelin record,” he wonders.

“What is it to score films or write a musical?

“We see the potential of these big projects, these things with lots of craftsmanship… when you’re really sharing with people the craft of telling stories and pushing yourself to do things you’ve never tried before, to sound ways you thought you never would before, to take on iconic artists’ sounds.

“We do this because of our love of writing great songs and things that will last through time and can be shared with multiple generations.

“That stays true, that’s always been true. That was true when we were kids – and it’s definitely true now.”

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