Singers who join Le Mystère des Voix Bulgares need not only an outstanding set of tubes but an impressive clutch of songs from their respective home regions in Bulgaria. What they don’t need to bring to the world-famous choir is a musical education, much less any vocal training. They pick up all the formal knowledge they require for the ensemble while rehearsing and touring. As for the bright and piercing style of its singers, that can’t be taught by anyone.

“Our singers are born with these voices,” says Dora Hristova, on the line from Toronto. Hristova is artistic director and conductor of Le Mystère, which comes to the Chan Centre for the Performing Arts this Saturday (May 24). “If you don’t have the right physiology you can easily do damage to your vocal cords, because the tension of the air passing through them is so great.”

One of the mysteries of this wild and intensely beautiful style of a cappella singing is how it came to be described in the West as “open throat”. It’s quite the opposite: the vocal cords are constricted, which increases the singers’ power and clarity and allows the articulation of complex musical ornaments. But the melodic range is limited; most Bulgarian songs span an octave or less.

While Le Mystère’s music may be ancient in origin, its presentation is relatively new. According to Hristova, it was only around 1950 that Bulgarian folksongs started to be arranged for multiple voices. “At first such choirs were without a conductor, but as the skills and professionalism of the singers grew, so they needed to be led.”

The ensemble was created in 1952, when Bulgaria was in the Communist bloc, and given the catchy moniker of the Bulgarian State Radio and Television Female Vocal Choir. Its breakout event was the release in 1975 of Le Mystère des Voix Bulgares, recorded by French musicologist Marcel Cellier. Thanks to fans such as Kate Bush and Bauhaus singer Peter Murphy, the album proved a huge and enduring international success. When the choir became independent of the state in 1997, it changed its name to the title of that seminal disc.

“Going freelance meant that we had more flexibility,” Hristova says. “Today, we’re not all women. There are two men among the singers in the [25-piece] ensemble coming to Vancouver, a baritone and a tenor. Our repertoire is drawn from all seven folklore regions into which Bulgaria is divided. Each of these has a distinct tradition of instrumental music, manner of singing, embellishment, and modes.

“Thrace, for instance, in the central part of the country, is known for its very rich ornamentation, its minor-key modes, and the very flexible voices of its singers, who have more than one octave as their range,” Hristova continues. “All of our members know and sing a lot of songs from their area, and I try to preserve the individuality of the singers. They’re able to copy other vocal styles, of course, but that’s imitation. They’re all at their best in the songs and style they grew up with.”