The Bulgarian Women's Choir, a group preceded by exceptional critical and popular acclaim, will come to Salt Lake's Symphony Hall at 7 p.m. Sunday, April 8.

Thanks to widespread exposure on record and through a 1988 sold-out tour of 13 American cities, the choir is being widely hailed with great anticipation for its current American tour, which will take the group at a slower pace to 25 cities.The choir was originally scheduled to sing here on Thursday, April 5, but took advantage of a chance for national exposure on Johnny Carson's Tonight Show, postponing the Utah date. (For a preview of the choir's style, watch the Tonight Show of April 5.)

The group's 1988 concerts and its popular recordings, "Le Mystere des Voix Bulgares Volumes I and II" ("The Mystery of Bulgarian Voices") on the Electra/Nonesuch label, have inspired such glowing comments as "the most beautiful music on the planet," "spiritual, even soulful depth" . . . "complex and sophisticated harmonic devices" . . . "eerily beautiful, mesmerizing." The first recording sold 200,000 copies, rising to the top of Britain's pops charts and establishing itself as one of the rare ethnic music recordings to achieve commercial success.

Danny Kahn is head of artist development for Nonesuch/Electra records. "My specialty is the exotic, and I have an open mind and ear for such things as Brazilian sopranos, creative rock groups, and this chorus," he said in a telephone interview. "You might say that I'm a professional listener."

Kahn "found" this choir music in Bulgaria and arranged for the first recording, supervised by Marcel Cellier and released in Europe in 1987. "The album got good reviews, but as with anything exotic, its offbeat nature made radio programmers skeptical. Acceptance came slowly," Kahn said.

"The choir is world renowned; it had always traveled Europe, Asia and Japan, also the Soviet Union and Eastern bloc. But its 1988 tour of the U.S. and Canada, while modest, captured the hearts of North America.

"This choir has a special quality, very attractive to the world audience. They sing folk music, once removed - music that arises out of oral, indigenous traditions, but whose polished qualities and arrangements are new and modern, in a magical way - an artful elaboration of folk music's timbres, rhythms and spirit," Kahn said.

"This style originated with Philip Koutov, who understood the basic importance of folk music in Bulgaria. He was the father of Bulgarian concert folk music," he said. "The Bulgarian State Radio and Television Female Vocal Choir dates back to 1952, when Koutov assembled the finest singers from various folk regions of the country into one group. He composed hundreds of works for the choir, based on song and dance traditions from all regions of the country. Koutov died in 1982 at the age of 79. Krasimir Kyurkchiysky has carried on this tradition by conducting and writing music for the choir, as well as opera and symphonies."

Hence the choir's repertory consists of songs traceable to such Bulgarian regions as Shoppe, Thrace (home of musicians honored by the ancient Greeks), the Rhodope Mountains, the Strandja and Pirin Mountains; also many songs and new arrangements by contemporary Bulgarian composers.

The choir of 24 singers will be conducted in Salt Lake City by Dora Hristova, with accompaniment by ethnic instruments - the gaida, tambura, kaval and gadulka.

In notes for the Nonesuch/Electra recording, commentator Ingram Marshall analyzed some of the tangible factors that constitute "the mystery of the Bulgarian voice."

"This music focuses on the strangely beautiful timbres of the Bulgarian female's voice, a very different sound, with a cutting clarity tempered by seductive loveliness, which ultimately enchants our ears," he said, noting "lively dances in asymmetric meters . . . , scales not based on major-minor tonality, harmonies which incorporate dissonant intervals as freely as consonant ones, and timbres, both vocal and instrumental, which seem more akin to Asian than European traditions.

"Many of their arrangements use two voices to track seconds, sevenths and ninths, rather than the more usual western use of unison, major thirds or sixths. . . . While a western chorus might struggle to intone and balance these dissonant intervals, for the Bulgarian women such diaphonic (dissonant) singing comes naturally.

"For us the diaphonic seconds want to resolve; for them, they simply float, and the childlike clarity of the Bulgarian voice aids them in making this dissonance crystal-clear. The second also plays a big role melodically. Large leaps are uncommon and most movement is stepwise, with the entire range of a tune sometimes limited to three or four notes."

Robert Sturm, a writer, translator and folklorist, traveled with the Bulgarian Women's Choir on its 1988 tour as translator, and visits Bulgaria regularly to study its folk music. He knows the singers of the choir personally, and finds them delightful representatives of the best in the Bulgarian nature.

"The Bulgarian people are very open, easy to know, they like to talk about their lives, they keep few secrets," said Sturm. "They are generous, they invite you into their homes to sing and eat and drink, and you seldom go away emptyhanded, for they love to give gifts.

"The women of the choir, ranging from ages 30 to 55, are nearly all married, with children and even grandchildren. Like professional women anywhere, when they travel they must leave families behind; and that's not easy, since they can't load the refrigerator with TV dinners. Food in Bulgaria is prepared from scratch, and Bulgarian men are not noted for their household skills. It's best if there's a grandmother around to take over!

"Most of the women of the choir are noted soloists, some have made solo albums for Bulgarian radio. Almost every one is a singer of note from her own region of the country. The diversity of their backgrounds is a great advantage, because when the choir works on a number from a given folk region there's always a native expert from there, who can help with the styling, musical detail, ornamentation, and accent of local dialect."

"Most of these women have been involved in music since early childhood," said Kahn. "Many of them have won contests in their districts, some have had special musical schooling, and many continue to compete as singers, a great southern European tradition. When they are selected for the choir, they move to the capital in Sophia, rehearsing and recording daily when not traveling.

"While most are not professionally trained, they work as professional folk singers, and they are highly disciplined. In a country where folk music is exalted, they are recognized as singing artists, interpreting a unique music with deep emotional communication. They think of folk art on a par with opera (another great Bulgarian singing tradition that has produced many international artists.)"