The plan was to talk to the husband-and-wife duo of Béla Fleck and Abigail Washburn, along with their 9-month-old son Juno, together over the speakerphone.

But, as with many of the best-laid plans involving an infant, this one gets foiled before it really gets off the ground. "Sorry, Abby had to step out to feed the baby," Fleck says almost immediately, and in doing so captures the family spirit at the heart of the couple's latest musical adventure.

Even now, five years after they tied the knot and almost a decade since they first started collaborating, at the start of Washburn's solo career, it's hard to believe that two of the most preeminent banjo players in the world ended up not only a musical partnership but a romantic one as well.

Even more surprising, in retrospect, is that the latter relationship has until now largely been just a footnote, as each has pursued their own artistic muses. Since touring together in the Sparrow Quartet in the mid-2000s, Fleck has continued working with his fusion band the Flecktones and producing a steady stream of jazz and classical music collaborations. He also starred in a documentary, 2008's Throw Down Your Heart, that followed the banjo virtuoso on a six-week trip through various African countries as he collaborated with more than 40 different groups and solo musicians.

Washburn, meanwhile, recorded a well-received, more singer/songwriter-oriented album in 2010 with collaborator Kai Welch (City of Refuge) and later wrote her first theatrical production, Post-American Girl, which tells the coming-of-age story of a young girl dealing with an increasingly globalized society.

Since last September, however, the two have begun regularly performing together as a duo, touring the country with their newest addition to the family and re-working songs from their respective careers into cozy two-banjos-and-voice arrangements. The pair will stop by the McGlohon Theater on March 28 as a part of their current tour.

Fleck likes to joke with the audience a few songs into each show "that it's dawning on them with horror that all they are going to hear for the whole show is banjo," but the duo's skill and eclecticism makes it feel far removed from your standard bluegrass performance. "We have cello banjo, baritone banjo, piccolo banjo, bass banjo and our regular banjos," Fleck rattles off. "And then we have Abby's beautiful voice. And we have a lot of diversity in the material too."

And while he is the first to admit the duo's shows "have a lot more traditional elements than anything I've done in a long time," Fleck insists that there is something a bit unique and natural about their recent concerts. "It's more about the sound of the duo, the sound of two banjos ringing and rippling together and Abby's voice on top, and the kinds of sounds the two of us can create. It really has its own integral point of view."

Perhaps for the first time more important than the particulars of the music itself, however, is the family-centered nature of the enterprise. Driven largely by the practical concerns of having a newborn and wanting to spend as much time as possible together, the two usually low-maintenance, itinerant musicians are traveling with a tour bus, blow-up pool for baby baths and a full-time nanny in tow.

"It's very sweet," Fleck admits. "It's like no other touring I've ever done in my life, but we are loving it."

Washburn eventually returns to the conversation after putting the baby down, and, although still fighting the lingering effects of a stomach bug, is similarly effusive about the new experience of touring as a duo with their new child.

"I think there is an exciting aspect to being a family on the road that actually makes [the performances] more appealing to some people," she says. "Just the humanity of a family, rather than just being performers separated so much by the fourth wall, is a big deal. The things we talk about on stage are really more relevant to the audience and bring us closer together."

And while there is no recording studio evidence as yet from the duo's new effort, a live recording from NPR on the Mountain Stage at West Virginia Wesleyan College suggests an unprecedented musical intimacy to their collaboration, with arrangements of a subtlety and patience that belie the banjo's usual driving force in traditional bluegrass music.

Fleck describes the origins of these takes on songs from across both their repertoires as an extension of the kind of off-the-cuff jams the couple would engage in at home, backstage or at parties before they began touring as a duo.

"It's really felt like a couplehood thing, like something we could do together that doesn't sound like anything else out there," Fleck says. "We've been able to musically be ourselves just like we are as couple."

For a partnership where music and romance seem inextricably intertwined, truer words could not be spoken.