Walking lightly: Ladysmith Black Mambazo, circa 2004.

Ladysmith Black Mambazo witnessed the birth of New Haven's Arts & Ideas festival. The festival in its inaugural year lined up the South African a capella group for a free concert on the Green.

Nine years later the group returns to Arts & Ideas. Will they sound any different?

Upon a few initial listens to their new release, Raise Your Spirit Higher [Wenyukela], a gringo has trouble telling what's changed. As always, the music is beautiful, calming, harmonious, spirited, uplifting, accented by the trills and percussive clicks of the group's native Zulu tongue. Just like on 1990's breakthrough Two Worlds, One Heart .

But subtly, the music has evolved, says someone who should know, Albert Mazibuko.

Mazibuko, a native of the group's eponymous town of Ladysmith, has sung with the ensemble since 1969. He saw the group achieve international fame after its collaboration with Paul Simon on Graceland .

"The style is the same. But the music is very different. Because now we have travelled the world and we sing with other people," Mazibuko says in a phone chat from an Amerisuites in Boise, Idaho, where Ladysmith checked in last week on the first stop of an eight-week U.S. and European tour. Playing with musicians from other traditions rubs off on the group's own music, he says.

The music has always been broadened thanks to an infusion of young new members, grandsons of group leader/founder Joseph Shabalala. Their influence has led to more English lyrics in the songs, Mazibuko says. And the younger members' final track of the new album, "Tribute," adds a hip-hop twist to the music. Leave it to Ladysmith to render rap in a soothing, smooth groove; "Tribute" consoles Shabalala after a gunman murdered his wife in a church parking lot.

"Black Is Beautiful," another track on the album, takes an old idea and celebrates it with quiet, understated mellifluousness rather than braggadocio.

That's because of the gentle roots of the music, a choral style known as "isicathamiya."

The term means "walk lightly, tiptoeing," according to Mazibuko. "You don't want to wake someone sleeping. This is the music born when our fathers were working in the mines," in the 1920s and '30s. After hours below ground, they'd make music in the above-ground compound. But they made sure not to disturb co-workers who'd fallen asleep.

T he biggest change from Ladysmith's last Arts & Ideas visit is the reality back home in South Africa. This concert celebrates the 10th anniversary of the end of that country's racist apartheid system--and, in the years since, the country ability to tackle its demons without violence and build a better society. Since then, South Africa formed a Truth & Reconciliation Commission to confront the abuses of the past era through a legal process rather than violent retribution.

So, whereas Ladysmith used to see its music as a vehicle for giving the South African people hope for change, it now sees its message largely as a celebration of that change.

"The South African people, they chose to live in peace," Mazibuko says. "Everyone was scared [about what would happen post-apartheid]. There were so many political organizations. They quarrelled.

"I remember the speech [Nelson] Mandela made in Durban the first time he was released [from jail, before becoming the country's first leader]. He said, 'Take all your weapons and throw them in the ocean and live in peace.' Everyone was relieved."

Thunderstorms chased Ladysmith Black Mambazo off the Green at their first Arts & Ideas visit; they filled Woolsey Hall instead. Whatever happens this Sunday--whether or not they end up outside--expect to feel the sun shining.

--Paul Bass