If Public Enemy's Chuck D joined Black Sabbath, the result might sound something like Rage Against The Machine. That rap/rock combination proved explosive when Rage Against The Machine performed for a full house Sunday night at the Astroarena.

Rage Against The Machine isn't the first band to meld hip-hoop and hard rock. Run-DMC and Aerosmith joined forces 10 years ago on Walk this Way. Ice T has had some success with his metal band Body Count, and the Beastie Boys have taken punk/rap to a whole 'nother level.

But Rage Against The Machine, which hails from suburban Southern California, might be the most unusual hybrid rock/rap band yet to hit the scene. The guitarist, Tom Morello, is an African-American Harvard grad. The lead vocalist, Zack de la Rocha, is a Mexican-American Bob Marley look-alike.

Rage Against The Machine was forced to postpone an earlier date in Houston because of de la Rocha's bout with strep throat. Given the strain he puts on his vocal chords, it's a wonder he can even make it through a show.

The band then made the crowd wait another 55 minutes after the end of an opening set by the Stanford Prison Experiment. But when Rage Against The Machine finally hit the stage with People of the Sun--from the platinum, chart-topping album Evil Empire--it had the crowd jumping from the start.

While the Beasties have the edge in terms of lyrical flow over de la Rocha, they offer nothing to compare with the sonic explosions laid down by the guitarist Morello and the driving rhythm section of bassist Tim Bob and drummer Brad Wilk.

Although he is the die-hard rocker of the crew, Morello wowed the crowd with his guitar imitation of turntable scratching during Bulls on Parade.

On songs like Bulls on Parade, Vietnow and Without a Face, de la Rocha shouts out a revolutionary social message similar to late '80s hip-hop groups such as Public Enemy and Boogie Down Productions.

On Bullet in the Head he warns about the perils of heedlessly following your gang or, for that matter, your government. With a powerful call-and-response chant of "They say jump, you say how high," the song demonstrates what is missing in these days of tired, gotta-get-mine gangsta-rap.

But the message is not what this 20-something-and-under crowd was after. Instead, it was moved by the pulsating, earth-quaking, ear-splitting blast of wailing guitar, thundering bass and booming drums.

With Bob, Wilk, and Morello wrecking shop, the mosh pit action on the arena floor was energized to a fanatical plane. The combatants--those who were not asked to leave early by the security, that is--were able to depart sporting smiles to go with their cuts, scratches, bruises and black eyes.

The Stanford Prison Experiment's 40-minute thrash-rock set seemed more like an experiment gone awry. The band had no presence and no concept of how to get the crowd involved.