NASHVILLE, Tenn. — If the sound of barbershop harmony invokes Norman Rockwell images of white men singing vaudeville-style songs in straw hats, organizers of the Barbershop Harmony Society are trying to update that image.

The society, which dates back to 1938, has been promoting research into the African-American origins of four-part a cappella singing and encouraging the spread of the musical style beyond North America. This year, the group recognized Grammy-winning black gospel a cappella group The Fairfield Four as honorary lifetime members.

The society held its annual international convention in Nashville, Tennessee, this past weekend, where about 6,000 people watched or competed. Barbershop Harmony Society CEO Marty Monson said the group has been working to break down cultural barriers and preserve a lost history.

“Really where it took its form was in the 1800s in the African-American barbershops, somewhere between Nashville, Memphis and New Orleans,” Monson said. “We’re really focusing on giving credit where credit is due.”

Current members of the Fairfield Four, formed in Nashville in the early 1920s, worry there may not be another generation of African-American singers interested in learning how to sing in harmony.

“It is becoming a lost art in terms of what we are seeing immediately,” said singer Bobbye Sherrell. “It’s scary.”