When college student and roots music fan Lance Ledbetter grew frustrated at the near impossibility of buying 78 rpm gospel records from the 1920s and ’30s, he began to ponder a question: What would it take to reissue those old tunes and put them in stores?

Answering that question has become a career for Ledbetter and his wife, April, at their record label, Dust-to-Digital.

Since its first release in 2003, the tiny company run from their modest brick house in a quiet Atlanta neighborhood has become a powerhouse in the niche market of music that’s been gathering dust, waiting to find or regain an audience: antique 78 recordings of blues, gospel, jazz and other styles, along with musicologists’ field recordings of rural musicians and indigenous people all over the world.

Nine of the label’s releases have been nominated for Grammy Awards, and one actually won.

They cover an eye-popping musical territory, spanning rural American blues and gospel, traditional Moroccan songs, Sacred Harp shape-note hymns, throat singing in the Tuva region northwest of Mongolia, storytelling and a host of other genres.

A unifying theme ties them together, April Ledbetter said: “I think it’s creating context and access for things that are otherwise hard to physically hear or mentally wrap your head around.”

In the indie music magazine Pitchfork, music writer Amanda Petrusich has written that it’s “astounding how essential . Dust-to-Digital has been to the preservation of traditional American folksong.”

And Chuck Reece, editor of The Bitter Southerner online magazine wrote recently that, “Lance and April Ledbetter are perhaps the most important preservers of folk music in the modern world, and they do it all from the basement of their little brick house.”

This month brings two new releases: collections of field recordings in Mississippi and from central and eastern Africa.

The Mississippi material represents another coup for the Ledbetters, whose earlier releases “Goodbye Babylon” and “The Art of Field Recording, Vol. 1″ gained widespread notice.

“Voices of Mississippi” was assembled from decades of field recordings by musicologist, academic and documentary filmmaker William Ferris. The material was drawn from his archives in the Southern Folklife Collection at the University of North Carolina at Chapel Hill.

The Yale-educated Ferris helped develop the academic field of Southern studies, serving as founding director of the Center for the Study of Southern Culture at the University of Mississippi and later teaching at UNC. But his work all stemmed from an early love for the African-American roots music he grew up hearing and later recording in his native Mississippi.

“His parents had a working farm. He was actually hearing it steps away from the house he lived in,” Lance Ledbetter said.

The second June release, “Listen All Around,” represents 1950s recordings made by British musicologist Hugh Tracey in central and eastern Africa. It’s pop music, Lance Ledbetter said, reflecting American music shaped by African-American roots, then broadcast back to Africa and transmuted again.

Like many other Dust-to-Digital products, these are highly visual as well as audible works of art. The “Voices of Mississippi” box set consists of three CDs and a DVD of documentary material produced by Ferris, along with a 119-page hardcover book containing essays on Ferris’ work, lyrics to the songs and photos made by Ferris. “Listen All Around” is entirely contained in an illustrated hardcover book, with two CDs tucked in the front and back.

The label’s first release, “Goodbye Babylon,” was a mammoth six-CD set — five CDs of songs and one of sermons — packaged in a cedar box along with a book and bolls of cotton from Lance Ledbetter’s uncle’s farm.

Drawn from the stashes of 78 rpm collectors — the only place much of the material was still preserved — “Goodbye Babylon” took the couple four and a half years to produce, from the time Lance envisioned it during their engagement until it was released in 2004 and quickly garnered a Grammy nomination.

His biggest moment came while listening to a National Public Radio segment in which rocker Neil Young touted “Goodbye Babylon” and said he’d been given a copy by Bob Dylan.

“I thought I was going to faint,” Ledbetter said. “I think that was actually the high point.”