Fall Out Boy kicking off 'Mania' tour at Nassau Coliseum

Fall Out Boy’s Pete Wentz has his own secret focus group for his band’s new music: His 9-year-old son, Bronx, and his friends.

“It’s not nuanced,” Wentz says, laughing. “But play something for a 9-year-old, and they’ll tell you if it’s a smash or not.”

And for Fall Out Boy, who made the unusual decision last year to scrap a completed album and head back to the studio, that kind of reminder of the power of music is invaluable, especially when the music industry is in the middle of another seismic shift. “It seems like the music industry, and really all of entertainment, seems to change every three to eight months,” Wentz says. “What happened with ‘Mania’ is that we didn’t know how much.”

In the end, everything turned out fine for the band. Fall Out Boy’s album “Mania” (Island/DCD2) hit No. 1 when it was finally released in January. And now, the band — bassist Wentz, singer-guitarist Patrick Stump, guitarist Joe Trohman and drummer Andy Hurley — is ready to start its "Mania" tour at NYCB Live’s Nassau Coliseum on Wednesday, Aug. 29.

“Tour is a great place to really connect people to the new songs,” Wentz says. “It can change the vibe of a song completely. When we put out a piano version of ‘Young and Menace,’ people saw it as a different kind of song.”

And the band plans to connect fans to the songs of “Mania” in all sorts of ways on the tour, while blending the new songs with the band’s varied back catalog. “It’s a magnification of the ‘Mania’ album,” Wentz says. “I grew up watching Guns ‘n’ Roses and Michael Jackson and you went to their shows, and there was always some moment when you thought ‘That really happened?’ You were part of a moment that was bigger than yourself. That’s what we want to give someone who hasn’t seen Fall Out Boy before.”

INSTAGRAM MOMENTS

Wentz says the “Mania” tour will feature a new stage setup and new visuals to give fans something to Instagram. Though some musicians aren’t thrilled about their fans spending concerts watching them through their phones, Wentz says it’s understandable.

“It’s a generational thing,” says Wentz, 39. “It’s a thing that didn’t exist when I was growing up, but if it did, I would’ve done it, too. Kids today are creating their own Circus magazine, their own Rolling Stone. . . . They want to be the creator of their content and to try to document it by taking selfies.”

However, Wentz hopes they balance living in the moment with documenting it. “I hope they take some of the show in,” he says. “Nothing is better than the sensory memory. The best moments are the ones you hold in your head. Textures are hard to put in a gif.”

And Fall Out Boy is looking to strike its own balance. “Everything’s not going to work all the time,” Wentz says. “We don’t have to be on the moon or on the Titanic. We have to be able to push . . . [On ‘Mania’] we liked ‘Last of the Real Ones’ and it turns out our fans gravitated to it, but we second-guessed it. We should have doubled down.”

After all, Fall Out Boy occupies a unique space in pop culture — one of the rare rock groups still played regularly on pop radio.

“It’s a fun place to be in the world,” Wentz says, laughing. “We can play a rock festival and be the poppiest band there. But when we play Jingle Ball, we’re like Slayer all of a sudden.”

He enjoys being a bit “subversive,” getting unorthodox songs like “Centuries” played in football stadiums or “Uma Thurman,” which samples the theme from “The Munsters,” on pop radio.

“We’re a bit of a pirate ship,” Wentz says. “We can adapt a little bit easier than others. We’re built to run and gun. We don’t need three years to plan. Of course, sometimes it’s a bit of ‘Ready! Fire! Aim!’”