After nearly 50 years celebrating its nation's culture, Ladysmith Black Mambazo is bringing in younger singers. Only two who accompanied the leader here Sunday were in the original a cappella group.

Ladysmith Black Mambazo, the a cappella Zulu men's choir from South Africa, has been celebrating its nation's culture for almost 50 years, and Sunday night's Kimmel Center show - attended by dignitaries including the South African ambassador to the United States - was significant on many levels.

When the eight-man group sang "Long Walk to Freedom" on the day before Martin Luther King Jr.'s American holiday, leader Joseph Shabalala made it a point to congratulate his native land, and the two men, Nelson Mandela and F. W. de Klerk, who were responsible for its change from apartheid to democracy.

In its presentation the group has always been somewhat bilingual - even the most deeply African hymns often had snippets of English content. Subtly but definitely, though, the sound of the choir has changed over recent years. The Mambazos are markedly younger, with only a couple of the men accompanying Shabalala Sunday having been among his original members.

Now among the members are four of Joseph's sons, including Thamsanqa Shabalala, the youngest and tallest. He has inherited Joseph's soft vocal timbre and playful personality, and it seems as if the 66-year-old leader may have appointed the 30-year-old singer, who has led a "second-generation" Mambazo choir in his homeland, heir apparent.

"This Is the Way We Do," from the Mambazos' newest disc, Ilembe, which is being released today, shows some of the youngest Shabalala's influence. On Sunday night, the charismatic Thamsanqa took the lead mike, bringing a younger, hip-hop influence to the group's simple but spectacular boot-dance-based choreography.

Nevertheless, Ladysmith Black Mambazo is still quintessentially traditional and South African. The harmonies - a deep, broad base of basses, with a sprinkling of tenor and alto - continued to shine. Songs such as "Shosholoza" and "Hello My Baby" contained the same I-IV-V chord changes and traditional ululations that make the Mambazos so listenable.

It must be pointed out, however, that these same harmonies, which have been the Mambazos' calling card for almost five decades, sometimes failed the group Sunday. On several occasions, the two or three highest parts, which sometimes included Joseph Shabalala, were obviously flat; it was as if the group's pristine harmonies were, for the first time, showing flaws. It was a disappointing development, sure, but not one that killed the enjoyment of what the Mambazos did that night, or what they have done.

- by Kevin L. Carter