After repeatedly hearing this new disc hyped by The Mars Volta leader Omar Rodriguez-Lopez in recent interviews as their “acoustic record,” TMV fans might be a bit surprised when they finally get to hear Octahedron.

Acoustic guitars highlight only a couple of the tracks on the new album, primarily the single “Since We’ve Been Wrong,” the over-7-minute “With Twilight as My Guide,” and “Copernicus.” The rest of the songs feature as much of the bombastic guitar and keyboard-driven rock as their fans are used to.

A special five-on-the-floor shout-out goes to track 2, “Teflon,” where vocalist Cedric Bixler-Zavala wails, “Let the wheels burn/ Let the wheels burn/ Stack the tires to the neck/ With the body inside.”

What strikes me as particularly “acoustic” about Octahedron is the lack of dense, arpeggiated guitar overdubs that typically define the Volta’s sound. In fact, the only guitar “solo” is placed at the end of “Luciforms,” the last song on the record.

The new songs are something the band could sit down and perform “acoustically.” And that may very well be what Rodriguez-Lopez meant. In the guitar-less space that’s created, Isaiah Ikey Owens’ piano and organ parts are allowed to shine through — something that’s struggled in the mix on past records. And Bixler-Zavala has again improved his ability to craft/graft melodies over the sonic maelstrom (most noticeable on last year’s Bedlam in Goliath) and not sound like the vocal parts were arranged months after the music was written.

To my ears, the band has decided to focus on songcraft, putting all their commercial eggs in the TMV (read: major label) basket — a keen business move considering their recent successes and touring opportunities — and leave the freaky, psychedelic improvisations to the many band side projects on Rodriguez-Lopez’s own label.