Gearing up for a gig at Prescott Park, David Wax discusses the Mexo-Americana band’s origins and recent success.

The David Wax Museum won an Internet contest last year to earn a spot in the 2010 Newport Folk Festival. The Boston-based group was one of the lesser known acts to take the stage, and yet it proved to be one of the festival’s highlights. After attracting a sizeable audience, the band members stepped offstage and performed acoustically in the middle of the crowd, drawing a thunderous roar of approval.

DMW returned to Newport on July 31, but this time they didn’t have to win a contest to get there. Over the last year, the band has earned significant national attention, appearing on National Public Radio’s “World Café” and other programs. Their second full-length album, “Everything Is Saved,” was released in February and earned glowing reviews from numerous publications. The group has emerged as one of the hottest indie bands on the circuit.

On Wednesday, Aug. 10, David Wax Museum will play an outdoor show in Portsmouth as part of the Prescott Park Arts Festival, taking the same stage where Tom Rush, Shawn Colvin, Taj Mahal and others have already performed this summer. Director Ben Anderson reports that attendance at the festival is up about 200 percent over last year.

Fans on the Seacoast know DMW from previous gigs at local venues like The Red Door, The Stone Church and The Press Room. But it’s been a while since the Museum came around, in part because of their growing demand around the country. 

That boost in popularity may have begun last year in Newport. Wax said just performing at the storied festival was a thrill.

“It was amazing just to be playing there at all, let alone that we got as much positive attention as we did,” Wax said. “It’s a place that has a lot of mystique for me, mostly because of Dylan’s 1965 performance there when he went electric.”

The acclaim their own Newport set garnered served as validation for a band that had been laboring to build a regional following since its formation three years earlier. David Wax Museum had entered a new chapter in its still budding career.

The roots of that career can be traced back to Deep Springs College, a liberal arts school located on a cattle ranch and alfalfa farm in California’s High Desert. David Wax, a Missouri native, was attending the school when he traveled to rural Mexico one summer to do volunteer community development work. He was stationed in the region of La Huasteca, about eight hours north of Mexico City.

“I happened to be living in a community with a lot of great musicians, and this type of folk music was a real integral part of life in this particular region,” he said.

Wax did not initially expect to start playing Mexican music, himself. But the experience opened his eyes—and ears—to new musical opportunities.

“I just became a fan and developed a passion as a listener,” he said. “That evolved over the years and kind of planted a seed in my brain that blossomed into this idea that I could go down there and actually study the music after I graduated from college.”

Wax finished his degree at Harvard and then returned to the Mexican countryside to study the music in earnest. He became familiar with three specific regional styles: Son Huasteco, from central Mexico; Son Jarocho, from the Veracruz area, and Son Calentano, from southwestern Mexico. He learned to play all three styles on jarana, a small acoustic Mexican guitar.

After returning to Boston, Wax met singer and fiddler Suz Slezak, a native of rural Virginia who had graduated from Wellesley College in Massachusetts. Wax convinced Slezak to get a donkey jawbone, a traditional Mexican percussion instrument, and learn how to play it. She did so, and the two formed the core of the David Wax Museum in 2007. A rotating cast of other musicians have supported the duo.

The nascent group played mainly at house concerts and quickly developed a comfort level performing intimate acoustic shows nestled in the middle of their audience. That mentality carried over into their early club gigs, where they often stepped out from behind the microphone to engage the noisy bar crowds. Local fans may remember seeing Wax and Slezak circling the floor of The Stone Church as they sang, or performing while standing on chairs in the middle of The Press Room. They pulled a similar stunt during their first Newport gig.

“It has become a common thing,” Wax said. “We don’t do it at every show. It has to kind of feel right.” 

By the time DWM released its first album, “Carpenter Bird” (2009), the group had developed considerable buzz in the area. The album features a mix of Mexican-inspired songs like “Colas” and “Beatrice” and folky American numbers like “Jalopy Heart” and “When You Are Still.” It’s a refreshing blend of jaunty, percussive rhythms and soft, sweet melodies that straddle the border between two divided cultures.

With “Everything Is Saved,” Wax and company have further integrated the Mexican and American elements of their compositions. 

“Something that we tried to do with the newest record, ‘Everything Is Saved,’ is to blur that line as much as possible,” Wax said. “Clearly, there are some songs that started out with a direct lineage from the Mexican tradition. With those songs we tried to think about ways we could bring in elements of Americana and indie rock and other world percussion ideas to make sure they had a foot outside of that world, as well. And, with some of the straight-up Americana songs, if that’s how they started in their origin, we tried to think creatively about ways that we could give them a Mexican flavor, whether that was in the instrumentation or in some kind of horn arrangement or by adding some kind of Mexican rhythmic part. So there was a real concerted effort on our part, led by producer Sam Kassirer, to kind of weave a thread through the record.”

They succeeded. From the opening track, “Born with a Broken Heart,” the album unites the exoticism of non-Mariachi Mexican folk music with the familiar edge of modern indie rock. And while other bands have taken a similar tack (Calexico is a case in point), few reach as deeply and authentically into Mexican custom as DWM.

With the exception of “Chuchumbe,” which is basically a loose translation of a traditional Mexican song, Wax typically writes original lyrics based around Mexican themes. A poignant example from “Everything Is Saved” is “Yes, Maria, Yes,” which takes its chorus from an old Mexican song but adds Americanized verses.  

“Basically, the verses are all original, although I kind of have an eye on the original (Mexican version) as I’m writing them, and I’m thinking about what the ideas of the original are and what the thematic elements are,” he said.  

The band plans to return to the studio in January to record its third album, and some new songs are already in the works. Meanwhile, their heightened recognition has enabled them to tour nationally and sustain careers as full-time musicians.

“It means that we can show up in a new town and instead of playing for five or 10 people that all have some direct connection to us, we can play for 50 people or 100 people who don’t have a direct connection to us,” Wax said.

They’ve still got a ways to go. Wax said recent shows in the Pacific Northwest were far from packed, and other indie bands (such as The Avett Brothers, with whom DWM once toured) are now playing large theaters and concert halls. But the mere opportunity to earn a living with music is almost surreal for Wax.

“When you start out doing it, you really want to believe that you can do it, but it really seems like a pipe dream, because it’s so hard for a band to make a living and do it in a sustainable way,” he said. “We feel really blessed that all the attention we’ve gotten has given us a foundation to be able to do this as a way of life.”

The concert begins at 7 p.m. on Aug. 10 at Prescott Park on Marcy Street in Portsmouth. There is an $8 to $10 suggested donation. For more information, visit www.prescottpark.org.