"Maths and Sex": The Pulse of Alt-J at Red Rocks

Since debuting with the beautifully eccentric An Awesome Wave in 2012, Alt-J (which has described its songs as being about "maths and sex") has become a stalwart at major music festivals around the world, sampling — and befriending — Miley Cyrus, picking up a Grammy nomination for last year’s This Is All Yours, and building successful 2013 and 2014 Fillmore gigs into last night’s sold-out headlining slot at Red Rocks.

As music bounced off the mountains with Denver looming in the distance, there was an element of Alt-J’s velvety, angular folktronica that transcended the English quartet’s refined romanticism – dipped in funk reminiscent of, though slower than, early-‘80s Talking Heads – to touch on the truly, gloriously ridiculous. Imagine the bleeding-heart lament of the Cure's Disentegration juxtaposed with more playful, danceable pop and a game of Mad Libs. At times, that pleasing ridiculousness brought to mind the two American guys who racked up over two million views on YouTube in May by aptly poking fun at guitarist/singer Joe Newman’s singular nasal playfulness and the group’s signature vocals-and-synth pulse.

But the young Brits impressively showed the big Red Rocks crowd (whose members are almost exclusively in their twenties and thirties) how lyrics that touch on math, sex with brooms, Japanese deer and references to both Roald Dahl and Maurice Sendak (sung not unlike Adam Sandler regaling a lunch lady) can translate into worldwide rock stardom.

“We’re so glad this night has finally arrived,” unassuming keyboardist/vocalist Gus Unger-Hamilton remarked after the atmospheric opener, “Hunger of the Pine,” from An Awesome Wave. “We’ve been looking forward to this pretty much forever.”

Unique drummer Thom Green, who mixes a gaggle of electronic drums with humble percussion (bongos, tambourine, etc.), shined on the sincerely weird “Fitzpleasure,” a darkly funny funk workout that essentially challenges listeners to pretend they know the lyrics. Newman’s abstract line “Deep greedy and Googling every corner” served as a quick prelude to Alt-J’s marvelous light show, which has expanded since the band played the Fillmore in October, altermately reminiscent of the indistinguishable, twinkling city lights far from Red Rocks or lyrically vibrating and changing shape along with the music. Spotlighting each Alt-J member and each song's nuances (which, notably, are driven at times by guitar, keyboards, drums or simply vocals), Alt-J's light show was a more focused, tasteful take on the kind of giant, “whoa”-inspiring light show for which Phish has long been famous.

Not that Alt-J is all fat, funky rock and irreverent lyrics supported by a kind of living, breathing stage set. Green, whose underrated loping style is highlighted by his choice to play without cymbals, is alone worth the price of admission to an Alt-J show if you can get close enough to see how he fluidly moves around the drum kit. Green suffers from Alport syndrome, which has rendered him around 80 percent deaf, and at Red Rocks, he was effectively Alt-J’s quarterback through subtle dream works like “Matilda” and oscillating, dance-inducing soundscapes “Dissolve Me” and “Every Other Freckle.”

Surprisingly, the nexus of Alt-J’s one-hour (only one hour?!) Red Rocks set — punctuated with a four-song encore that, like the Fillmore show in October, ended with the twisted sing-along, “Breezeblocks” — was Newman and Green’s a cappella duet “The Ripe & Ruin.” The quixotic piece of poetry, which seems like a riddle when you actually read the lyrics, froze many in the 9,500-strong Red Rocks crowd before the band melted into “Tessellate.” There's nothing quite like that mid-summer moment when a group of musicians in their prime (treating us to that sweet spot before they've written any songs that suck) make a huge, legendary outdoor venue feel impossibly intimate.