Produced by Wilco’s Jeff Tweedy and Patrick Sansone at the Loft in Chicago, Wassaic Way finds Guthrie and Irion pushing further beyond the folky sound they established on 2005’s Exploration, their first studio LP. After Irion’s solo album Ex Tempore in 2007, the live album Folksong in 2009 and the children’s collection Go Waggaloo in 2009, the pair began expanding their sonic horizons on 2011’s Bright Examples, an album that drew praise from American Songwriter magazine for its “lush, dreamy sound.”

“This record is a departure from a folk duo,” Irion says. “I think this is the best example we’ve been able to present that shows the many facets of what we can do. There’s loud guitars, there’s soundscapes, there’s a lushness to it, there’s a popness, an edge. But that can be difficult sometimes to bring it all together and present it.”

Wassaic Way is also the latest entry in an ongoing creative relationship between the Guthrie family and Wilco. Sarah Lee is the daughter of Arlo Guthrie, and the granddaughter of the iconic folk singer Woody Guthrie, whose unfinished songs Wilco recorded with Billy Bragg on a pair of Mermaid Avenuealbums in 1998 and 2000. Wilco also invited Sarah Lee and Johnny to perform at the band’s Solid Sound Festival in 2011, and the duo had toured with the Autumn Defense, Sansone’s project with Wilco bassist John Stirratt.

After recording most of Bright Examples live with a band, the duo credits Tweedy and Sansone in helping them put the new songs together in the studio. They had plenty of material to choose from: Before convening in Chicago last year, Guthrie and Irion sent along nearly 50 demos for Tweedy and Sansone to sort through. Once they got to the Loft, Tweedy pushed them to revise and tighten up the tunes they had decided on.

“We actually ended up rewriting a lot of these songs with Jeff in the studio,” Guthrie says. “We would powwow on a song before we got going on it, sometimes for two hours at the beginning of the day, just me and Johnny and Jeff, making sure it was lyrically sound and there were no musical loopholes.”

You can hear it throughout Wassaic Way, in the buoyant pop of album opener “Chairman Meow,” the wistful melody threading through an enveloping beat on “Not Feeling It” and the moody atmospherics underpinning “Nine Out of Ten Times.” Guthrie and Irion also haven’t abandoned their folky roots, as demonstrated by the harmonica and Dobro on the lilting acoustic number “Hurricane Window.” Tweedy and Sansone played on the album, along with multi-instrumentalist Charlie Rose and drummer Otto Hauser, which they recorded in bursts over a period of a few months.

“It was the first time we’d ever taken our time with a record and really gotten it right,” Irion says. “When I listen to the album, there’s not much I would change, and that’s hard to say with other records we’ve made.”

Although Guthrie and Irion perform as a duo, they rarely write that way. With all the time they spend together on tour, and at home raising their two daughters, writing songs is more of a solitary pursuit for each of them. As studio dates approach, they share what they’ve come up with and offer suggestions and ideas.

“Writing is kind of an escape from the work that we do together as a family and on the road,” Irion says.

“It definitely echoes exactly who we are,” Guthrie chimes in. “Johnny’s full of melodies and really creative chord structures. He’s constantly working on a song that’s better than the last one. I tend to be a lot simpler, and sometimes songs tend to flow through me, rather than me crafting it as much. I’m a lot lazier than him.”

Irion adds, “I end up writing a bunch of songs, and Sarah Lee will write two, and one of them will be the single.”

Any of the songs on Wassaic Way could be a single, which speaks to the strength of the songwriting, and also to Guthrie and Irion’s underlying goal: they wanted an album that moves them one step closer to getting at the heart of who they are as writers and performers.

“Every record has been a huge learning curve, and you get pushed beyond your limits, and then your limits are way bigger,” Guthrie says. “I think we’re still at the beginning of what we can do as recording artists. I think we’re just starting to carve a path that we can walk on.”