The Mars Volta's San Antonio show makes it clear the band can both challenge and entertain a crowd

El Paso-bred prog machine The Mars Volta brought its sonic and visual insanity to San Antonio’s Boeing Center at Tech Port on Tuesday night. The group blew the minds of its devoted, cultish fans with a blazing set highlighting classic material.

But it wasn’t just labyrinthine compositions that gripped the audience. Flashing nights upped the intensity, reflecting off eyeglasses of the bespectacled, largely middle-aged crowd. And “crowd” is the right word, as the packed GA area produced a whiff of sweat to offset the potent smell of weed. It’s likely the beer vendors weaving in and out of the crowd before the set did solid business.

Despite the seven-piece ensemble on stage, The Mars Volta is a duo at its core: Cedric Bixler-Zavala on vocals and Omar Rodríguez-López on guitar. They got their start in the legendary post-hardcore outfit At the Drive-In, and their partnership has endured for three decades, punctuated by periodic public fallouts.

Perhaps the emotion of their relationship parallels the intensity and depth of the music. The major innovation of The Mars Volta is bringing progressive rock song structures and phrasing into the world of post-hardcore. In the past, denizens of these two worlds were blood enemies. At the Drive-In began moving in this direction though not aggressively as The Mars Volta.

When it formed, The Mars Volta leaned in hard to the prog, resulting in a run of out-there records whose most shocking move may have been their popularity, given the difficulty of their contents.

The Mars Volta play prog, punk, jazz, Latin, lounge — just about everything. Yes, they switch genres up, but it’s woven together in a way that is less about boundaries between styles and more about just playing them all at once.

There’s also a mid-period Led Zeppelin element to its music. Maybe it’s Bixler-Zavala’s high-end wail. Maybe it’s Rodríguez-López’s guitar wizardry.

But more likely it’s simply a commitment to bringing challenging sounds into rock 'n’ roll, a form that’s often grounded in four-four time and blues traditions.

The Mars Volta took the stage bathed in muted blue light and a nearly omnipresent, trippy synth, going in varying degrees all night. The continuous stream of sound made attendees feel as if they were watching a sci-fi epic rather than a rock concert. Indeed, the pacing reinforced the feeling that the whole thing was a related narrative.

In shadows, the band opened with “Vicarious Atonement,” from its third LP, Amputechture. The song is pretty much just singing, and the opening line “Don’t you pretend / That I’m not alive,” gained new relevance in this spot, a subtle reference to the fact that this tour — it started in Dallas last September — is the band’s first in over a decade.

The tour was preceded by a long-awaited new LP — The Mars Volta — which found the eclectic band giving up its weirdest effort yet. Not because it was crazy prog, but because it was the opposite: an accessible album of three-minute songs rooted in traditional structures without blazing instrumental virtuosity.

Regrettably, the band only played two songs from that album Tuesday night, meaning that new material accounted for about six minutes or so of the 95-minute, encore-free set. Indeed, of the 12 songs played, nine were from the first two records: three from 2005’s cheekily-titled Frances the Mute and six from the 2003 debut De-Loused in the Comatorium.

For a band that’s prided itself on forward momentum, the focus on 20-year-old material was vaguely disappointing. That minor quibble aside, the show absolutely killed. The audience reaction affirmed the band’s choice.

After “Vicarious” wound down, the weird noises that mark “Roulette Dares (The Haunt Of)” blasted over the PA and immediately showed what the band can do: hard-charging, twisty riffs that contrast with dreamy, ballad-flavored sections, a contrast that is the beating heart of The Mars Volta.

Firing up the Boeing Center’s Tesla coils near the end of the show was the cherry on top. They spat lighting, seemingly under the control of Rodríguez-López’s guitar noise.

The crowd singalongs were striking, particularly given that the lyrics prompting group participation were “exoskeletal junction at the railroad delayed.” Not exactly Top 40 verbiage. Plenty of bands have original sounds, and plenty of bands have memorable songs. Only legends have both.

The epic “L’Via L’Viaquez” followed, and the audience sang along to the catchy, Spanish-verse melodies. The Mars Volta is proudly from El Paso, and their use of intermittent Spanish lyrics highlights the border town that spawned them: sometimes English is spoken right next to Spanish.

And the band isn’t just proud of El Paso. Before the closing segment of “Son et Lumiere” and “Interiatic ESP,” Bixler-Zavala noted the band has a long history with San Antonio. “We never played at Tacoland, but we knew it,” he said. He also noted that many bands he loves hail from SA, and said that the recently reunited Glorium is his favorite.

The evening began with Teri Gender Bender, a frequent collaborator with Rodríguez-López in bands including Crystal Fairy and Bosnian Rainbows. The sound of her solo work is akin to Le Tigre. Rooted in dance music but actually indie rock in a different outfit. The set had a creepy, foreboding quality, created by the sinister bass ooze of the band in contrast with Gender Bender’s almost sunny presentation.

In the end, the evening provided challenging music for an audience that thrives on challenges. The songs may have aged, but they remain the same. Fans have had a couple decades to learn the ins and outs of the Mars Volta, but this is far from mainstream hard rock or metal.

The band’s dedication to flouting musical expectations begs the question how well it went over with the Red Hot Chili Peppers’ crowd. After all, Mars Volta is opening some of dates on the Top 40 funk-rock act’s current tour — although not its Wednesday show in the Alamo City.

It’s easy to picture RHCP fans scratching their heads to this stuff. And just as easy to guess that Bixler-Zavala and Rodríguez-López wouldn’t want it any other way.