Fred Kingsbury, of Walpole, Mass., directs Harmony Heritage.

PROVIDENCE — On the fifth floor of the Rhode Island Convention Center — high above a soggy sidewalk crowd waiting for admission to a beer festival — the lilting sound of melodic humming floated down the hallways and fallen sequins sparkled on the carpet.

Women in glittering costumes whisked to and fro as choral groups from across the United States and Canada prepared to test their mastery of an a cappella music style that originated in the early 1900s with the advent of barbershop quartets.

More than 2,000 contestants from about 80 different groups dedicated to the four-part harmony style known as barbershop singing converged on Providence for a four-day event that culminated Saturday with the competition of the chorus groups.

The event, which started midweek with workshops and competitions for quartets, is the premier annual competition for Harmony Inc., a women’s singing organization dedicated to preserving the art of barbershop music.

“Over the years, women across the United States and Canada have shared the joy of barbershop singing,” Jan Delvecchio, president of Harmony Inc. said in a statement. “Singing with Harmony Inc. has given our members the opportunity to share their love of music with the community and friends.”

While it is critical that the group’s four-part harmony arrangements remain true to barbershop style, there was a lot about the competition that was a long way from men in blazers and straw skimmers singing “Sweet Adeline.”

For one thing, most of the groups competing in the 2009 international competition opted for a lot of pizzazz in their outfits. Glitter, sequins and crystals abounded in custom-made costumes. The Capital Chordettes of Ottawa, Ontario, even added a flapper theme with beaded wraps and shiny headbands topped with red ostrich feathers

The groups varied in size from two dozen to more than 50, and their selections were as diverse as their hometowns. Some favored traditional songs like “Georgia on My Mind,” while other adapted more contemporary tunes from movies and Broadway shows.

The key, according to Christine Hayes, director of Silk ‘n Sounds from New Haven, Conn., is that the vocals be carried by the traditional barbershop mix of tenor, lead, baritone and bass parts.

Hayes and Fred Kingsbury, director of Harmony Heritage from the Pawtucket-Attleboro area, said that one feature that makes barbershop singing unique compared to other choral music is that the melody is not carried on the high notes by the tenors, but is carried by the lead singers who are in the middle of the musical register.

“It’s unique because there is harmony above the melody coming from the tenors,” said Harmony Heritage member Barbara-Ann McIntosh. “That’s one of the things that make the barbershop sound so recognizable.”

Another component that is particularly important in barbershop singing competitions is the ability to deliver a song with style. In some cases Saturday that meant dance steps, theatrical gestures or, in one instance, the donning of clown noses, in the middle of a song.

“Our job is to take the song from the sheet music and carry that message to the audience,” said Kingsbury.

In the warm-up room, the groups practiced their moves, their pitch and also took time for deep breathing, group hugs and sometimes a simple prayer. “Don’t let it bother you that there’s a rock band below us,” Kingsbury said shortly before his singers took the stage a couple of floors above the sounds of the beer festival. “Just be the actors you need to be for the songs.”

In addition to hoping for winning scores from the judges, each of the groups were also aiming for a little musical magic that comes with barbershop singing.

When all the voices are in perfect pitch and harmony, Hayes explained, there is a ringing effect as if there were a fifth vocal part –– sometimes referred to as the overtone or the angel’s voice.

“That’s what happens when it all comes together perfectly,” Hayes said. “That’s what gives you goose bumps.”

bpoliche@projo.com