Ranky Tanky was supposed to be a side project among a group of friends from South Carolina.

Their plan was to make a few videos, record an album, play about 15 dates a year. Meanwhile, band members Quentin Baxter, Kevin Hamilton, Quiana Parler, Clay Ross and Charlton Singleton would maintain their busy lives. All were adults with families and established music careers.

Then NPR's Terry Gross heard their eponymous debut album, released last October. Soon Parler, Ross and Singleton were booked for a December date on "Fresh Air."

Gross asked them to sing some tunes. When Parler sang "O Death," it was killer. When Parler and Ross harmonized, it was heaven.

"Terry Gross isn't exactly in the business of breaking unheard bands," Ross said. But something in the music touched a lot of people.

In January, following the "Fresh Air" broadcast, "Ranky Tanky" went to No. 1 on iTunes, Amazon and the Billboard jazz charts. Van Morrison, Diana Krall and Kamasi Washington ate Ranky Tanky's Lowcountry dust. Fifteen gigs turned into 50, then even more for the year 2018. On Friday, the group will play in Minneapolis for the first time.

Ranky Tanky's songs are simple, mournful, playful. Some are spirituals. Some are children's rhyming games. One is a lullaby. Another teaches, "You better mind how you talk/You better mind what you're talking about/You got to give an account at the Judgment/You better mind."

The rhythms are can't-sit-still catchy.

All are refreshed versions of old songs from the Gullah culture. Gullah people — descendants of West Africans who were enslaved and brought to the South to grow rice and cotton — still live along the Carolina coast and on the Sea Islands. They have their own traditions and language. "Ranky Tanky" is a Gullah term that translates (loosely) to "get busy," "get funky" or "work it."

Four of Ranky Tanky's members — Baxter, Hamilton, Parler and Singleton — have Gullah roots. They grew up with Gullah music in church. The fifth, Ross, is white. "I grew up United Methodist and went to a very nonrhythmic church," he said. "Church music, to me, was the worst thing ever."

Starting the band was his idea.

"Gullah was always this mystery close to home for me," Ross said. "I always wanted to learn more about it and learn more from it. I'm a disciple of the music and the culture. They're descendants."

The four men have known each other for 20 years. Ross plays guitar, Baxter drums, Hamilton bass and Singleton trumpet. They formed a jazz band out of college and worked together until Ross moved to New York City 17 years ago. They stayed in touch, though.

"Gullah was infused in everything [Baxter, Hamilton and Singleton] were doing as jazz artists," Ross said, "and they're some of the first jazz artists who inspired me. So Gullah was a cultural thread for them, and I'm a person that's interested in culture.

"I find African diaspora music in the Americas to be the most interesting music in America," he continued. "The collision of African, European and indigenous people tells a complex story that's filled with hardship and challenge. But what was forged through that hardship and challenge is something truly beautiful, like coal being pressed into a diamond. To me, Gullah music is one of those diamonds. It's something that was born in our home state, born in our backyard, that we can share with the world, and it has a powerful impact on people."

'We respect the ancestors'

Ranky Tanky began as an instrumental group. When they decided to bring in a singer, Ross called Parler.

In 2003, she placed in the top 48 of Season 2 of "American Idol." That led to national tours with Clay Aiken, Kelly Clarkson, Miranda Lambert and Maroon 5. (Aiken is her son's godfather.) Parler also has a popular party band in Charleston, playing weddings and corporate gigs.

"When Clay [Ross] called me, it was right around the time when I was on a spiritual journey," Parler said. "I'd been on the road for years and had a pretty successful band back home, but I felt like there was something else I was supposed to be doing — like something was missing.

"I didn't know what it was, so I said, 'I'm going to be still and be quiet until it comes to me,' and it did. It was a phone call from Clay. I've known everybody in the band since I was a little girl."

The band made a series of videos Ross used to shop Ranky Tanky around. "I knew videos would get the ball rolling more than an album. We had four videos, all black and white, and we booked 20 shows — quality shows at performing arts centers, theaters and festivals. The videos created opportunities to be together. Being together created opportunities to realize that what we were doing had potential."

The arrangements are infused with jazz, gospel, funk and R&B. "There was never the intention to do a period-piece re-enactment of a bygone era," Ross said. "We wanted to take the timeless qualities of this music, and the melodies, rhythm, stories and feelings. The descendants of the culture in the band are the quality control. There's never an inauthentic moment."

"We respect the ancestors with our approach to the music," Parler added. "There's still that rhythmic feel of what I grew up in."

"Generally speaking, there's a real excitement that we get from the elders in the community," Ross said. "People see that we're honoring the culture and the music."

Still, as the only white person in the band, "I get the kind of comments you would expect to hear," he said. "While we're signing CDs post-show, some clever audience member will say, 'Pretty fly for a white guy,' or whatever. But I've never experienced any kind of cultural-appropriation accusation, or anything like that.

"I understand there's a very clear line, and we talk about that a lot. I need to make sure I don't speak out of turn about things I don't understand, no matter how close I am to the situation. That's true for anybody hanging out in a culture they weren't born into."

Pamela Espeland is the Artscape columnist at MinnPost and blogs at bebopified.com.