No strangers to fermenting together disparate ingredients, it was probably only a matter of time before wonk-poppers Alt-J joined bands like Iron Maiden, Elbow and Hanson on the craft ale booze-wagon. For £3.50 a can, Scottish fans could sample their new liquid merch, a moreish 6.5% US-style IPA called Absolutely No Worries, although for a group who seem to embody the fractured, jittery experience of life in the 2010s, that insistently reassuring name seems almost certainly ironic.
But these are good times for the off-kilter Leeds trio, who won the Mercury in 2012 with their debut album An Awesome Wave and have quietly surfed upwards ever since. This short UK tour – coinciding with the release of Reduxer, a hip-hop-heavy remix record that enjoyably expands their slimline third album Relaxer – culminates with two special concerts at the Royal Albert Hall that will combine strategically deployed speaker pods and advanced sound-mix management for total musical immersion. For acolytes of their silky auditory topiary, experiencing Alt-J in 360-degree surround sound without headphones will surely be a heavenly gig; for non-believers, the thought of being bombarded with finicky folktronica no matter which direction you turn might sound more like a Black Mirror episode.
Despite a slightly stiff atmosphere in this all-seater venue, enthusiastic cheers greet keyboardist Gus Unger-Hamilton, singer/guitarist Joe Newman and drummer Thom Green as they form a democratic row in semi-darkness. Each is dressed in anonymous black and boxed in by a framework of ingenious floor-mounted and hanging light bars that, variously, resemble tubular bells, gigantic guitar strings and eerily dangling jellyfish strands.
Ever since their debut, Alt-J’s fondness for modal chord progressions and devotional singing has suggested a band more interested in vespers than Vespas, even if early highlight Every Other Freckle injects a sleazy blues riff into all the flutey folderol. If they have a secret weapon – over and above their urge to wrestle eccentric synth tones and complex drumming into something as soothing as a colliery brass band – it is Unger-Hamilton and Newman’s exquisite harmonising, every bit as synchronised and impressive as their shimmering light show.
When it all comes together, the effect can be transcendent. Amid the wilderness hymn Hunger of the Pine an incongruous Miley Cyrus sample is expertly folded into the melange, alongside John Barry-esque horn stabs. During the delicate lost-love ballad Adeline, it seems as if stars ascend into the cosmos in a fibre optic ballet as Newman croaks soulfully about Tasmania. Elsewhere, over the course of 17 songs, the cumulative effect sometimes feels more like sonic morphine, or perhaps the wooziness caused by ingesting too many strong IPAs.
Things noticeably escalate for the encore after Unger-Hamilton politely invites fans to flood into the space in front of the stage. There is some good-natured frugging to the insouciant, matriculated-hobo blues of Left Hand Free, while the brassy skank of In Cold Blood – now boosted by a Pusha T rap verse lifted from Reduxer – remains the best song to feature a “binary solo” of chanted zeroes and ones since Flight of the Conchords’ The Humans are Dead. For all their attempts to push things forward, Alt-J are smart enough to recognise when they got things right first time, finishing with their breakthrough hit Breezeblocks, a spindly song that still packs a wallop.
• At Town Hall, Leeds, 23 October. Then touring until 30 October.
