Remember when hip-hop was more about stylistic innovation than thuggish threats and materialistic boasts? Human beat box Rahzel does. On his playful and assured debut album, "Make the Music 2000" (MCA), Rahzel follows in the sneaker imprints of Doug E. Fresh, Biz Markie and the late Buffy of the Fat Boys by using his voice to mimic the beats made by a computerized drum machine and other sounds associated with hip-hop. But where in the past the beat box has primarily been used as a gimmick, Rahzel, who comes to the 9:30 club Saturday, is raising it to the level of art.

On the current radio hit "Southern Girl," Rahzel's ticking beat box provides a warm and airy backdrop for singer Erykah Badu's charming free-form embrace of Southern stereotypes: "I'm a Southern girl/ Countrified/ Everything I eat is fried/ Got a Southern drawl/ I'm so country y'all." Listening to the song, it's hard to tell whether the booming backbeat is being made solely by Rahzel. But the album credits make it clear: "This track contains no instruments, no samples, nothing but pure vocals."

Throughout "Music," Rahzel radically expands the beat-box canon of sounds. On "To the Beat," with rapper Q-Tip, he imitates violins, organs, bass and guitar. And on "Steal My Soul," he pits his best horn imitation against Branford Marsalis's award-winning saxophone.

Rahzel's virtuoso tour de force is "If Your Mother Only Knew," a two-minute interlude recorded live in concert, where Rahzel performs the chorus of a song and the beat behind it at the same time. The effect is as astonishing as watching an acclaimed illusionist or a circus contortionist. You're left slack-jawed, wondering, "How'd he do that?"

In the video for the funky Pete Rock-produced single "All I Know," Rahzel's prowess is fancifully explained by depicting him as a hip-hop cyborg with a noise-generating computer chip in his head and a microphone jack in his right hand. But while admittedly eye-catching, these images miss the whole point of Rahzel's appeal. On "Music," he's not a cold, beat-spewing automaton but rather the sentimental favorite in a rhythmic battle of man vs. machine.

(To hear a free Sound Bite from this album, call Post-Haste at 202-334-9000 and press 8173.)

GZA: 'Beneath the Surface'There are many reasons why the once-infallible Wu-Tang Clan has fallen from hip-hop's highest heights, some of which are found on "Beneath the Surface" (MCA), the latest album by founding group member Genius, also known as the GZA. The album contains all the elements of Wu-Tang's trademark sound: the foreboding strings, the ominous piano tinkles, the unrelenting hypnotic beats. But at this point, the sound has neither the shock of the new nor the wow of the improved.

GZA's rhymes, which were so compelling on his last album, "Liquid Swords," also seem dull and uninspired this time around. The track "Publicity" is GZA's follow-up to his previous album's clever "Labels," which incorporated the names of numerous record companies into a rhyme. "Publicity," which similarly utilizes magazine titles, has a staid, "been there done that" quality, as does much of the album. At best, it reminds you of the captivating "Liquid Swords." And at worst it makes you wish that you were listening to that album instead of enduring its plodding successor.

(To hear a free Sound Bite from this album, call Post-Haste at 202-334-9000 and press 8174.)

CAPTION: The human beat box Rahzel, left, and Wu-Tang founding father GZA.