Dawdling Easter parade

Fans nodded like mules. The barkeep was reading a book. There was no sex. Still, Easter Sunday at Hollywood’s Henry Fonda Music Box Theater with Isis and friends was a night of extreme rock music -- extremely slow. As for excitement, you just had to recalibrate your notion of what that means.

After the sludge cycles of Zozobra and Jesu, the wider dynamic range of L.A.-via-Boston’s Isis might have seemed a transgression, but the crowd (20s, dressed down, facial hair prevalent) who populated this big old movie palace clearly thought otherwise, salaaming with heightened intensity as each crescendo peaked.

As unprepossessing guitarist Aaron Turner conducted with his hopeless croon and desolate throat-roar, a lighting scheme of several vertical white spots emphasized the quintet’s democratic character as it chimed and crashed through an endless series of simple, melodic riffs that easily vibrated the entire space. Manning three guitars and a keyboard/computer (Clifford Meyer, the hippie in psychedelic tunic, switched between), Isis augmented the textural depths of its albums with crushing volume; drummer Aaron Harris’ stately accents drove the spokes.

Overall sameness cost Isis some momentum, which was regained and then some in an encore boosted by a shivering, dub-influenced electronic workout that recalled the band’s craziest recorded moments, the outside remixes of the 2002 album “Oceanic.” If the vibe wasn’t especially rockish, Isis generally encourages more contemplation than perspiration; Turner also masterminds the group’s austere album designs, and the lines at the T-shirt stand testified to the spectrum of his art.

Isis spearheads a phalanx of bands that includes Pelican, Red Sparowes and Lesbian. The movement’s appeal of womblike sonic immersion is unpopulist but growing. Audience member Jeff, a longtime fan who ranks the band as a heaviness fave alongside Neurosis and Mastodon, was asked about the state of mind appropriate to approaching this music. “Isis,” he said, “puts you in a state of mind.”

Former Old Man Gloom bassist Caleb Scofield hauled the opening quartet, Zozobra, through a droning, unvarying set distinguished by enveloping loudness and the fine quality of its feedback.

Anticipation pushed higher for the trio Jesu, an underground resurrection featuring guitarist Justin Broadrick (of the lamented heavy mood unit Godflesh) and drummer Ted Parsons (Swans, Godflesh). Despite Jesu’s somewhat heightened consciousness of structural power, it took Isis to get attendees to uncross their arms.