Jaded music professionals still talk about the surprise of hearing the debut Take 6 album when it appeared in 1988. What could have been less promising than an a cappella gospel album by an unknown sextet from an Alabama college? The music that jumped off "Take 6," though, was astonishing. Applying sophisticated jazz arrangements to traditional hymns, the singers swung the rhythms crisply and spread the harmonies boldly, but instead of the hip detachment of jazz, they offered the passionate commitment of gospel.

The rest of the story is well known: Take 6 became industry darlings, winning a gold record and three Grammys and singing on albums by Quincy Jones, Joe Sample, Don Henley and Johnny Mathis, and on the soundtracks for "Do the Right Thing" and "Dick Tracy." Now, after 2 1/2 years, the group has finally released its long overdue second album, "So Much 2 Say" (Reprise). The surprise is gone, but the complex arrangements and flawless execution are as dazzling as ever.

A cappella singing has often proved limited in appeal, because most a cappella singers only feel comfortable in a few major keys and in a few tonal colors and because they rarely produce the kind of strong, funky bottom that American music emphasizes. The members of Take 6 have overcome those limitations by training themselves to sing in many keys and many colors, with the bottom bolstered by Alvin Chea's deep bass and by the group's percussive grunts, vocal pops and hand claps. As a result, Take 6 doesn't wear thin as quickly as most a cappella groups.

When they race through the new album's title tune at high be-bop speeds, scattering harmony notes in all directions, the six singers not only astound with their vocal acrobatics but also reinforce the song's theme of "so little time (and it flies when you're having fun)." When they layer their voices in soft vowel harmonies on the slow hymn "Come Unto Me," the sound is lush and inviting. When they tackle "I'm on My Way," Chea's bubbling bass line and the other sliding glissando voices tilt the song off-balance just enough to make the traditional hymn sound fresh.

The nine songs on the album are joined by four short snatches of sound effects and verbal banter that soon grow tiresome. The overproduced final track, "Where Do the Children Play?," is a bid for mainstream R&B radio, but is bland and pedestrian compared with the rest of the album. Much better are "Time After Time," an up-tempo song full of intricate rhythms and counterpoints, and "Something Within Me," a tribute to the Southern gospel "quartet" style that first influenced Take 6.

'Spike & Co.: Do It A Cappella' One thing that the new Take 6 album fails to capture is the infectious humor of the group's live performances, where the singers are more likely to approach their arrangements with loose playfulness rather than stern precision. You can hear the difference in their performance of "Roll Away Jordan" on the new soundtrack album "Spike & Co.: Do It A Cappella" (Elektra). Compared with the careful studio version on their first album, this live version shows them taking spontaneous chances -- and having fun doing it.

This live album features six different a cappella acts on 13 songs, all taken from the recent PBS TV special directed by Spike Lee. Take 6 appears just once on the album, but the a cappella revival sparked by the group brings much deserved attention to some other overlooked acts. New York's Rockapella is a four-man group specializing in rock-and-roll repertoire and novelty items such as its calypso arrangement of "Zombie Jamboree." True Image, the sextet from "The Cosby Show," tries to revive the classic doo-wop a cappella of the 1950s.

As they recount in their autobiographical song "Looking for an Echo," Brooklyn's Persuasions have been carrying the a cappella flag, through thick and thin, for 28 years now. Lead vocalist Jerry Lawson is more of a rough-voiced soul shouter than a doo-wop singer, and he leads the group through three rousing gospel-soul numbers. The album's biggest revelation, though, is the Mint Juleps, an all-female sextet from England that adds a new-wave edginess to its sound. When Debbie Charles sings the keening, yearning lead on her "I Want to Live Easy," her three sisters and two friends create a nervous, popping, rhythmic harmony behind her.

The album's highlight pairs the Mint Juleps with Ladysmith Black Mambazo on the South African song that became a doo-wop hit, "The Lion Sleeps Tonight." The rising-and-falling harmonies of the six British women are set against the gruff chants and warrior cries of the 10 South African men; the understated arrangement sounds both relaxed and ominous. Ladysmith, of course, has become one of the world's leading a cappella acts since it joined Paul Simon on his "Graceland" album and tour. The group appears twice more on "Do It A Cappella," singing the work song "Down in the Mines" and the patriotic anthem "God Bless Africa."

Ladysmith has two other releases in the stores right now. "Classic Tracks" (Shanachie) collects 14 songs from the group's pre-"Graceland" releases, with a welcome emphasis on strong melodies. It's the best possible introduction to the group's original, indigenous style. By contrast, the new album, "Two Worlds One Heart" (Warner Bros.), finds Ladysmith moving past its traditional a cappella sound for fruitful collaborations with George Clinton, the Winans, Ray Phiri and their bands.

Bobby McFerrin: 'Medicine Man' Why form an a cappella group when you can sing all the parts yourself? Bobby McFerrin has been doing just that for most of his career, and his new album, "Medicine Man" (EMI), was largely created by the singer taping his voice again and again on multiple tracks. The layers of vocals build up until the songs are as richly rhythmic and harmonic as anything by Take 6 or Ladysmith Black Mambazo.

The real triumph of McFerrin's new album, though, is his breakthrough as a songwriter. As he proved with his 1988 smash single "Don't Worry, Be Happy," McFerrin is more than a one-man scat band -- he can also come up with pop music's most precious commodity: the hypnotic melodic hook. The dozen songs on "Medicine Man," all written by McFerrin, are bursting with hooks. And just as Take 6 does, McFerrin adds enough bass and percussive vocal sounds to give his hooks the bottom weight required for American radio.

The title track boasts not only a spry Brazilian hook (to reinforce the lyrics' image of a Third World healer), but also a repeating "instrumental" riff -- scat voices going "di-di-whoop-whoop." "Baby" recalls Ladysmith Black Mambazo in the way it sets gruff chants against a falsetto wail, but it also adds a jazzy, romantic lead vocal. "The Garden," has an easygoing Caribbean feel, like McFerrin's hit, but with South African township harmony chants. "He Ran All the Way" sets graceful falsetto sighs against a pattern of driving, low vocal rhythms.

McFerrin does get some help on a few songs. "Common Threads" is a slow, wordless, mesmerizing duet between the singer and jazz keyboardist Lyle Mays. McFerrin leads his Voicestra, a nine-voice a cappella choir (including such women's music stars as Linda Tillery and Rhiannon), in call-and-response on two gospel-influenced numbers, and two Latino percussionists catalyze the accumulating momentum of "The Train." Mostly though, it's just McFerrin and his amazing voice, making the Brazilian flavors of "Angry (Gima)" and "Soma So de la de Sase" as captivating as anything on the new Paul Simon album.