In the hollow square, it doesn't matter that Agnes Roberts thinks she can't really sing.
"It matters that I want to," she said. "It matters that I use the voice God gave me."
Her voice is a sacred harp, a term that Ms. Roberts and singers like her use to describe the ultimate instrument given by God.
The term is used interchangeably with "shape note singing," a music notation system that uses triangles, diamonds and rectangles instead of traditional round notes.
The difference isn't just on paper. The music is loud and democratic. Anyone can join a singing, even without musical training.
That's just the point. Shape note singing hails from an era of the American church before the organ or organized choirs. It was developed as a way to teach Colonial congregations how to sing together without instruments or formal training.
While the music is most often found today in rural churches and fellowship halls, shape note singers produce a sound with all the heft and bravado of a cathedral organ.
Ms. Roberts, 85, learned it as a child in south Georgia.
"I use to go to the sings with my mother and daddy as a little bitty thing, and I'd sit on the front seat and sing my little heart out with my dad. They would try to get me to lead, but then I was rather shy and I refused. I wouldn't do that," said Ms. Roberts, who now lives in Augusta.
The leader stands in the center of a hollow square formed by members of the sing, who turn their chairs to face one another.
"To hear the voices all blended together in that hollow square is just simply beautiful, and you don't realize it until you hear it in person," she said. "You can hear all of the different voices coming at you."
She often joins sings in Savannah or Macon, Ga., because there isn't an active group in Augusta.
A few weeks ago, she and five friends traveled to Barnwell, S.C., for a workshop on shape note singing.
A diverse crowd of 30 gathered for the sing, led by Robert Kelley, a professor of music at Lander University in Greenwood, S.C.
Most had never sung together before. Because of shape note notation, they're able to sight read and sing in harmony, even with strangers. The shape of the notes provides cues.
"They don't focus on making a beautiful sound. They sing it how they want," Dr. Kelley said.
It runs contrary to Western classical tradition, but "there are a lot of folk traditions where you sing at the top of your lungs and just go for it. This is one of them."
Dr. Kelley started studying the tradition three years ago.
"I wasn't aware of shape note singing as a living tradition until one of my students discovered it and took me to a singing," he said.
His students' interest has contributed to a revival of shape note singing, he said.
"Just over the past 20 years there's been a resurgence of shape note singing across the country," Dr. Kelley said of the music, which had all but disappeared in South Carolina in the early 20th century.
Young people find they often have plenty to learn from shape note singers.
"This tradition has created a few musicians, that while not trained, can sight sing better than some of my students. There's something to that," he said.
The music has made its way not only into classrooms but also pop culture. It was featured in the movies Cold Mountain and Gangs of New York , said Matt Hinton, a documentary filmmaker in Atlanta.
In 2008, he released Awake, My Soul , a documentary of shape note music in the South. Mr. Hinton and his wife, Erica, recorded the footage over seven years. Even in that time, he saw the medium grow.
"At my first sing virtually everyone was older. The average age was 60s or 70s. Today there has been such a renewed interest, not only in the South, but all over the world. It's not uncommon to find people in their 20s and 30s saying, 'Yeah, this is cool,'" Mr. Hinton said.
Ms. Roberts is glad for it.
"I find that more and more young people are going, are beginning to get into sacred harp, which is wonderful. I am so glad they're trying to carry on the tradition that has been existent so long," she said.
Reach Kelly Jasper at (706) 823-3552 or firstname.lastname@example.org.
A FOUR-PART SERIES
SUNDAY: Raccoon hunting
MONDAY: Shape note singing
TUESDAY: Picking parlor