Of course, as any fan of The Mars Volta’s sprawling acid-rock epics will attest, where you start isn’t necessarily where you end up. The eight songs that make up Octahedron [Warner Brothers] don’t surf the same unrelenting waves of amplified aggression as 2007’s The Bedlam in Goliath, but they aren’t entirely unplugged, either. What’s clear is that Rodriguez-Lopez found direction in the limitations he imposed on himself and lead singer Cedric Bixler-Zavala.

“I came up with a list of ground rules to push us to create something different,” he explains. “An obvious one was to ask Cedric to sing in the middle and lower registers, because he’s known for singing way up high, and to use only three extreme vocal effects [such as the distorted Leslie cabinet that drives the closing track “Luciforms”]. I allowed myself only one instrumental section on the whole album, and I stayed away from writing horn sections or anything elaborate. All this was a big key in developing a different sound.”

There were restrictions on the actual recording sessions, too, which took place over the course of three weeks last summer at his E-Clat Studio in Brooklyn (since relocated to Mexico, where he now lives). Everything was tracked digitally to 48 tracks on Pro Tools—a real limitation, considering most Mars Volta albums have taken up in excess of 100 tracks, usually recorded raw to 2-inch tape, and then dumped to Pro Tools for editing and mixing. In a sense, Rodriguez-Lopez was turning back the clock to the way he and Bixler-Zavala made music with At the Drive-In, their first band together, and a cult punk fixture to this day.

“This time, we still mixed down to tape, and we mastered from tape, as we usually do,” he clarifies. “But again, making Octahedron was about making decisions up front that we would have to be stuck with. I loved the sound of the room I had at E-Clat, so I wanted that to be present, with the bleed and everything. We turned all our gear up to 10, for lack of a better term, and let it be a little furry in places, knowing that recording digitally can be so pristine.”

When tracking Thomas Pridgen’s drums, for example, that furriness sometimes meant overloading the room mics—usually a combination of Royer R-121s, a Royer SF-12, and a Neumann U 67—and recording “really hot” through a bank of Neve 1073 mic premps and Urei 1176 compressors. Also, a TASCAM 4-track 1/2-inch tape machine would often be running, to be mixed later into the overall sound. It’s a technique that gets an added twist on the hauntingly funky “Teflon,” where Pridgen’s drums and Juan Alderete’s muscular bass lines are chased by dreamlike echoes—via a Maestro RM-1B Ring Modulator—of the programmed beats Rodriguez-Lopez laid to 4-track back in 2001, when he first conceived of the song.

Octahedron brims with moments like these, the sound hovering at times between the contemplative spaces of early King Crimson and early Pink Floyd. “Since We’ve Been Wrong” quietly builds toward a Mellotron-fueled climax that offers a plaintive counterpoint to Bixler-Zavala’s midrange vocals. On “With Twilight as My Guide,” Rodriguez-Lopez strokes his Telecaster into erotic slides of abandon, recording through a phalanx of vintage Roland RE-101 and RE-201 Space Echoes, and a Supro combo amp close-miked with an SM57 and a Neumann U 67 from across the room. The track pivots on John Frusciante’s double-tracked acoustic guitar tracks that are hardpanned right and left.

The album’s arguable turning point is the single “Cotopaxi,” which finds the core members of the band locking into one of their trademark hypersyncopated grooves. Rodriguez-Lopez takes pleasure in explaining how it signifies where he and his mates are as a symbiotic unit.

“I usually like giving the band their parts right before they’re going to record, without any time to practice, so they have to fight for their lives at that moment,” he says. “This one was different because I taught it to the band during a soundcheck in Poland, so we got to play it a few times. Don’t ask me why, but I thought a lot about Cream for some reason, and the fact that before they all went their separate ways, they were a tight-knit group, and had a real psychic connection between them. So this was the one song that I did play with everyone in the room. I did it as if we were a band, and we were all aware of what was coming, and where it was going. I think it really shows how far we’ve come, not just as band members, but as family members.”