It's showtime for Six60 as they take their new album global

Six60 have big plans for their new album, Castle St. Photo / Matt Clode

They've grown up in the public eye. Now at the height of their powers, Six60 tell Rebecca Barry Hill they're only just getting started.

Above the couch is a framed photo of a stadium crowd – 50,000 swarming bodies. Ironically, only a few people fit inside this building, with its fully stocked bar, wall-mounted TV and baby piano.

It's a replica of Six60's uni flat at Castle St, the grungy Dunedin abode where the Kiwi band's hallowed success story began. The "tiny house" is situated at Eden Park, where the band have gathered with whanau, friends and media on a stormy Friday evening to celebrate their fourth studio album, also named Castle St. Social media star William Waiirua, TV journo Mike McRoberts and members of Supergroove mingle in one of the stands as Champagne corks continually pop.

Six60's lead singer Matiu Walters, wearing a jacket emblazoned with the words "Castle Street" morphs between music star and doting dad as his partner Caren hands him their 16-month-old daughter Boh for a cuddle; lead guitarist Ji Fraser and wife Jacquie are here with their two young girls, Fleur, 3 and Lucia, almost 2, as are keyboardist Marlon Gerbes, drummer Eli "Drumstick" Paewai and bass player Chris "Macca" Mac, in aviators and a red leather jacket.

It's a relatively chill scene for the most commercially successful Kiwi band in history, a group that has dominated the music charts here, each of their preceding albums reaching number one and achieving multi-platinum sales.

There's been a tell-all documentary, five New Zealand Vodafone Music Awards, sell-out gigs at both Western Springs Stadium and Eden Park (Six60 are the only Kiwi act in history to have headlined either).

Dan Carter, Chlöe Swarbrick, Sir Dave Dobbyn and uber-producer Pharrell Williams are all fans. Yet as they tell their supporters, they're only just scratching the surface.

"We just want to reach our potential and write the best music possible," says Walters of their global ambition.

It's two days earlier, and Walters and Fraser have joined Reset on a Zoom call from Los Angeles, before the band perform at the 500-odd capacity Troubadour following a show at New York's iconic Bowery Ballroom, then on to album promo gigs in Vancouver, Toronto and Chicago.

After a few weeks back home, it's then on to Amsterdam, Hamburg, Berlin and London before returning Downunder (where they'll play Eden Park again on November 19). Though Walters looks relaxed, in a black polo and baseball cap, anxiety levels are high, he says.

"We're debuting music to crowds who've never heard us. But it's been received well and we're sounding really good."

Though Six60's international popularity is patchy compared to home, that could be about to change. The band played a sold-out tour of New Zealand last year while the rest of the world isolated, the footage beaming to incredulous audiences around the world.

ITV's Good Morning Britain host Piers Morgan called them "the hottest band in the world right now", a sentiment echoed by NME and the Telegraph.

This tour has seen them play smaller, albeit legendary venues by design. "And that will inevitably lead us to the big stages and the big moments," says Walters.

Yet with young families at home, they're highly aware that comes with a price.

"It's been really difficult," says Walters of leaving baby Boh while touring. "She's at an age where she's changing a lot very quickly. It's pretty tough to be away when she's picking up new words and she looks different when I'm talking to her on Zoom."

"It's incredibly tough," adds Fraser, whose own experience as a parent makes him Walters' agony aunt, along with Mac, a dad to a 13-year-old girl.

"There are two sides to our lives. We get to do all these amazing things – travel the world, have the time of our lives. But we sacrifice things like the little moments with our daughters. When they're young they grow so fast. You go away for two weeks and when you come back they're doing something different."

If you thought hearing a stadium of fans sing every lyric back to you was bliss, that's nothing compared to seeing your offspring make their mark on the world. That's the general theme behind Before You Leave, the first single from the Castle St album, much of which Walters says was inspired by his daughter. Boh features in the music video alongside Walters' dad, as does the singer connecting with his whakapapa in a waka slicing through the Auckland harbour, the band jamming on a volcanic hillside.

Six60's new album Castle St has just been released. Photo / Matt Clode

Castle St was written when the world was in turmoil. But lockdown came at an optimal time for the band, who were holed up together in LA. It was a joyful experience, says Ji. The songs came effortlessly. Never Been Tonight and Good Wine are quintessential Six60 summer anthems that remind us life is short. Far Away, So Close tackles loneliness. Say it Now is an ode to speaking your truth, a great example of the album's light and shade.

"It feels so us," says Fraser. "We feel so exposed for the first time in a while, which is really exciting."

"For us, making albums is actually a process of personal change," adds Walters. "You're confronting what you believe and how you see the world and you're actively going about trying to change it, and trying to improve your creative process. You have to dig in deep and get honest and start cutting away the bullshit. And that's a tough thing to do because you're not just writing songs that are all earworms and structure and form and science, but the magic and the spirit of something deeper. Maybe we've gotten better at doing that. Definitely for me, this album is the best thing we've done because I know it's really honest and true. Which is what makes me nervous about releasing it."

What was supposed to be a week in LA lapsed into six months. Living in close quarters together, writing music in their kitchen and living room, made the band deeply nostalgic for their Castle St flatting days, as fresh-out-of-high-school buddies "thrust into freedom with a bunch of booze and the struggles of studying", says Walters, who managed to scrape through with a law degree.

"Even though [Castle St] was a terrible place to live – it was freezing and probably mouldy and all sorts of unhealthy things – I remember it fondly as the birthplace of something incredible," says Fraser, whose design studies soon gave way to music.

"We had lots of great friends around us and we had such a rich life on that street. It's created this crazy life. It was heaps of fun."

There were plenty of therapeutic breakthroughs. Particularly for Fraser, who quips that he finally put an 8-year-old guitar riff to good use on Nobody Knows. Hang On is their hopeful spin on the pitfalls of fame – namely, those who try to cut you down, something they've faced their fair share of.

As they've matured, they've become better at dealing with tall poppy syndrome and criticism, say the pair, who admit it was tough to experience in the early days. Six60 wasn't your typical edgy Dunedin rock band, after all.

"You allow yourself moments to be angry or whatever – you're not happy about it," says Walters. "But we did all our growing up in front of the people of New Zealand. I think that might be why we're so endearing to home because we just got on with it, wrote songs and put them on the radio, a bit of number eight wire."

Since breaking through with rousing tunes like Rise Up and Don't Forget Your Roots, they've gone on to confound their detractors who dismissed them as "BBQ reggae", challenging themselves to create everything from infectious dance to soulful rock-pop, unapologetically putting emotion at the heart of their songwriting.

The guys suspect that much of the early resistance had to do with those unfamiliar with the band thinking they hadn't paid their dues, when in fact they'd been gigging for years before they made it.

"We were these underground darlings and then you put one song on the radio and you're just put through the wringer," says Walters "It's weird because you come to America and it's so optimistic here and everyone is just so quick to support. Why don't we just celebrate the success in New Zealand and egg people on and create more opportunities for people?"

Last year the band put their money where their mouth is and purchased 660 Castle St. Then they established Six60 Scholarships, including a $10,000 rent rebate for music students, plus mentoring from the band and access to Otago University's new recording studios.

Inspired by having children of their own, Walters and Fraser say the band recently formalised Massive Entertainment, the record label they founded when they first formed the band, to allow them to help upskill the next generation of music stars, including Perth-based Māori band Coterie, and singer-songwriter Spencer Coyle.

"We could have used that when we were coming up," says Fraser. "There have been moments throughout our career that have been incredibly hard – roadblocks we just didn't see coming, whether it was label stuff or just how to be good as a band it's always been a dream of ours to help a lot of kids through that, rather than go through what we experienced which was a lot of loneliness in our search for the top."

Today they refer to each other as "brothers" but there have been times their family dynamic has fractured. During a bleak period in Berlin, they stopped talking to each other. Eager to repair their broken ties, they reached out to the All Blacks' mental coach Gilbert Enoka. He gave them emotional tools they still use today.

"Communication is obviously paramount, and being able to talk succinctly and directly without taking anything personally," says Walters. "Just being in each other's corner, someone having your back, and letting them know, it is huge."

Gilbert also impressed upon them the importance of acknowledging each of their successes, no matter how small. Materially, there has been a mix of "outrageous" not-so-guilty pleasure purchases and sensible investments. A Tesla. Real estate. Elsewhere they've put their earnings into equipment, studio time, their artists – and of course their families. But they've also learned to invest in the simple act of appreciation.

"You just get so fixated on your drive and your ambition," says Walters. "As soon as we sold out Western Springs we were backstage talking about the next thing to do! It's crazy when you think about it."

They've got better at celebrating, he laughs, even if it's something they've instinctively known how to do since Castle St.

"We're pretty good now. But I just don't care about the kind of things I used to. There's something so much bigger than hitting goals. You can enjoy it a bit better if you can just chill out."