It's probably safe to assume that the first-ever musical instrument was the human voice. Even before folks started banging sticks on stones, like prehistoric Keith Moons, they were "oohing" and "aahing" with some semblance of melody. Millions of years later, the voice remains the most honest way of expressing emotions. Besides, it's universal: No matter what their native languages are, singer and listener will likely connect on some level. That's one of the reasons the South African a cappella group Ladysmith Black Mambazo has been so successful throughout the world for more than 30 years. Its gorgeous harmonies span the gamut of sounds — from quietly compelling to silky smooth to subtly rhythmic.

The ensemble was formed in mid-'60s by Joseph Shabalala, who, after a spiritual epiphany, brought together seven bass voices, a tenor, an alto, and his own yearningly warm, slightly quavering lead in a mix of traditional Zulu choral music and Christian church tunes. Since then, Ladysmith Black Mambazo has sung everything from Zulu folk music to funky street-corner doo-wop and roof-raising gospel.

The group has recorded more than 30 albums during its four-decade career, but it's best known for instilling Paul Simon's Graceland with genuine South African voices. It's also appeared on numerous film soundtracks (Cry the Beloved Country, The Lion King) and on albums by Dolly Parton, Josh Groban, and Ben Harper over the years. Ladysmith Black Mambazo's latest CD, Ilembe: Honoring Shaka Zulu, pays tribute to the 18th-century African warrior. Expect to hear some songs from it as well as many from the group's vast catalog when they come to town this week.

-- by Mark Keresman