It may be hard to believe, but it's been more than 25 years since Hanson became a band. Their infectious hit "MMMBop" is now 22 years old. But Isaac, Taylor, and Zac Hanson, originally from Tulsa, Okla., show no signs of slowing down. This week, they released their newest album, String Theory, which features their biggest hits and some deep cuts — all reworked into full orchestral arrangements with the help of Oscar-winner David Campbell (who also happens to be Beck's dad). The band is following the release with a tour that includes a full orchestra. They'll perform  on Sunday at the Tower Theater in Upper Darby. Ahead of this performance, Taylor took some time to chat about Hanson's newest musical direction, what it's like to be part of a band that's had such a long career, and what their fans look like now.

How did you guys come up with the idea of incorporating a string orchestra into this tour?

The original kernel of the idea really began as we were thinking about the future as we celebrated our 25th anniversary. You have these ideas as you go through your career, like things you'd like to do. It's rare to reach a point where you see the stars align. After we finished our last tour, we felt like it was time to just take it up a notch.

Why did it feel important to share this new style with your fans?

We felt like it was important to tell a story and to challenge our fans and to put something truly different in the trajectory. The reason why we're doing what we're doing, we've always made each project, judged it based on our interests, sometimes it aligns with what's popular and sometimes not. But you have to do what's interesting and challenging to you so you can bring that to your audience.

How would you describe this new musical direction for people who haven’t followed Hanson since the beginning?

It's truly a musical experience from top to bottom. The String Theory show is one long arc, musically. As for the actual sound of it, it's a fusion of pop craftsmanship with grand symphonic interpretation. We want people to take away a sense of awe and feel like they're being taken away by the music and lifted up by it. So much of what you do with music is creating a connection with someone. Songs are one of the things that people feel like they have ownership over because it's connected with experiences that they have. They transport you. You can be in a certain place and the music can pull you into a different place. String Theory is taking that core idea of transporting and just bringing in all this musical arsenal.

When you were digging through your back catalog for unreleased songs or hits to turn into string versions, what did that process look like?

It was a big task to figure out what not to include. There were so many potential songs. We agreed to include historic songs and new ones. We tried to focus on the story and the lyrics so we could take the audience through an evolving journey, beginning with the idea of aspiration and reaching for the dreams that seem impossible. After we crystallized what songs to include, it came down to a combination of lyrics, musical mood, the build, the rise and the fall. We staggered songs that lift you up and songs that take you to a moodier place, and we were excited to put in songs that people know well.

Were there any particular challenges that came with working with orchestras and string arrangements for the first time?

It definitely stretched us and it was exciting because so often you're really insular when you write an album in a studio. You're doing it alone, maybe with a few other collaborators. In this case, you're sharing your ideas, versions, and arrangements. It was a very fluid but challenging process because you think you know what the song is going to be, but then the key needs to change. You thought this song should be here, but it's too long, so you have to change the length.

You guys have had a really long career in music, longer than many bands. What are some ways you make sure you’re always challenging yourself when it comes to making new music?

The reason why we started as young as we did was because we were already motivated. Making music and being creative is in each of us. For me, it's a part of who I am. It's a part of who we are. That's an aid to the longevity of a career. All you can do is to show up each day and give something. Then you turn around and look back and it's like, 'Wow we have 20 years behind us now.' It's hard to do anything at a high level. It's hard to maintain any career, and so one thing that was a real aid to us was learning about work ethic and not dodging the work. There was never a point where we thought this would be really easy, so when it's hard, it's not surprising.

How do you think the meaning of “MMMBop” has changed over the years for the people who grew up listening to it?

What that song is about rings more true now than ever. It really is about holding on to what really matters. Time flies by and you sort of have to find those few things that really count. You have to invest in people and experiences that are really meaningful. That song is in the show for that reason, and we play it with acoustic guitar and percussion, just the way it was written. You can hear the lyrics and the little bit of melancholy that's in that song.

Is it weird to be dads and also have been teenage heartthrobs?

We lived a pretty unorthodox life, so it definitely has its strangeness. Being heartthrobs was never something we clung to. It was never a goal to have our faces plastered on bedroom walls. I know what it's like to be a fan of something. It's very humbling and meaningful to realize that we have connected with different people at different points in their lives. There are fans who have grown up with us and now they're parents and have their kids, and there are people who have discovered us along the way. I'll look out over the crowd and see someone and I'm like, 'I think you're younger than our first record.' [Laughs] You can't control how people connect with your music. You can only control what you put out into the world and enjoy getting to be a part of their stories.

MUSIC

Hanson

8 p.m. Sunday, Tower Theater, South 69th and Ludlow Streets, Upper Darby, $39 to $60, 610-352-2887, venue.towerphilly.com