Getting Heavy at Tattoo the Earth Festival

Volume matters. Heavy metal is also supposed to be about escape and energetic fun--a place to vent youthful angst, to dance and roar freely.

The members of the band Slipknot would seem well-suited to that task with their masks and other cartoonishly macabre props, like KISS and GWAR before them. But they seem like the last ones in on the joke.

Slipknot was all about ego and defensiveness on Saturday at the Tattoo the Earth festival, held at the National Orange Show Events Center in San Bernardino.

While fans moshed happily in the heat, the headliners chose to spend several minutes of an hourlong set ranting against some unnamed rock star who dared call Slipknot “a Mickey Mouse band.”

The ‘Knot has often been subjected to jokes and disregard from various corners, largely because of the Des Moines, Iowa, band’s costumed image. But the success of its recent million-selling album, “Slipknot,” suggests that combining a driving metal sound with high-concept production was a savvy commercial move.

While Slipknot’s performance Saturday offered some well-played if extremely limited metal, it had noticeably less depth than others on the bill. Slipknot isn’t about to take hard rock into any exciting new directions, even with its tribal beats.

Second-billed Slayer also conducts itself with great seriousness, but these veterans exuded self-confidence in a way that Slipknot didn’t even approach. From its first moments on stage, Slayer fired out precise, rock-hard riffs. Its approach was also limited, but its sound was so polished and direct that the band came off as something more akin to a speed metal version of early Black Sabbath.

Tattoo the Earth was a showcase for the most primal and simplistic of hard rock. Georgia-based Sevendust was a typically raging presence, whether attempting Lynyrd Skynyrd’s “Sweet Home Alabama” or some other abrasive riff designed to fuel some welcome hard rock escape. And sets by the likes of Amen, Hatebreed and (hed)pe cranked out dependably grinding metal while headbangers waded into the Orange Show pond or bought a new tattoo.