LIVE & LOCAL

Nobody says much, and the bassist wears a tie. That’s about all the description you need of Yes, Inferno’s stage presence tonight. To be fair, the guys in YI play a sometimes-ambient brand of post-rock (i.e., “music without singin’ on it”), though, so not much more’s expected of them than occasional closed-eyed rhythmic swaying and the sweet relief of build-and-release song structures.

The classic b’n’r cycle that’s come to define grand-scope instrumental bands most often defined as “epic” or “cinematic” (Explosions in the Sky, Godspeed You Black Emperor, etc.) is ever-present tonight, but YI, in a few instances at least, play with the form enough to make it their own.

Opener “Imperfect World,” unfortunately isn’t one of these instances. Christen Saenz, dressed for dinner, plucks a blood-bubbling Pixies-style bass riff, a cavernous valley across which guitarist Richard Garcia broadcasts nimble-fingered Morse code. After a few minutes of this, the guitar line becomes telegraphed, and the (spoiler alert) big, noisy, knob-twiddling resolution looms tauntingly on the horizon like a desert mirage. “Imperfect World” proves the band has mastered gloaming textures, but it’s more atmosphere than song. You can easily imagine a vocal part, and that’s never a good thing in instrumental music.

So follow-up “Tunnels in London” is all the more stunning for blowing its wad so early on. Garcia drops his chiming, instantly catchy guitar riff almost immediately to pick up something heavier — a chugging, 120-decibel chalkboard scratch that’d belong in an ’80s-era Metallica song if it weren’t for the softening touches of Rey Hinojosa’s infinitely melodic keyboard. The drastic structure change happens every few measures, but drummer Ernst Bredvad keeps the band in seemingly perfect synch.

Bredvad’s on his feet for “Brain Insertion,” a manic-depressive track that owes more to Pink Floyd’s “Set the Controls for the Heart of the Sun” than anything Tortoise or EITS ever released. If Hinojosa’s off-kilter keys are like an out-of-tune carnival organ accompanying a malfunctioning android circus, Garcia’s guitar is the robot ringmaster, shooting sparks from his eyes, crushing the skulls of audience members too popcorn-bloated to get the hell out of his way. At one point, it seriously looks like his right hand is performing the shocker on his guitar at Mach 5. Then his hand blurs and disappears completely.

“We’re going to take it down just one little bit,” Garcia announces before “Gamma Minor,” a song that builds like a rocket launch but stalls and explodes before it leaves earth’s atmosphere — and he’s telling the truth. Nothing else on the set list packs the emotional intensity of “Tunnels” or “Brain,” and Garcia’s guitar reverts to killer-robot mode a few times too often, but with a little more variation, these guys will make kick-ass openers for former Dallasites Secret Machines on October 1.