[caption id="attachment_1409" align="alignnone" width="300" caption="By Josh Sisk"][/caption]All personal irritation aside due to a certain individual fist pumping and view-blocking throughout much of the xx's set at Sonar on Friday, this event, upon later reflection, says something important about the band's music. Critically acclaimed artists are often relegated to dwindling album sales and the art-rock crowd, but the xx's appeal is not isolated to skinny jeans and flannel. The Sonar crowd had more than its share of ironic mustaches and messenger bags, but the presence of Polo Ralph Lauren button ups and a few pairs of Air Force Ones made it apparent, all pretentiousness aside, a "good" taste in music is not something held only by those with a Goodwill wardrobe. The best music is something of which everybody can love.To a sold out, packed-like-sardines crowd, Class Actress opened the night with lead singer Elizabeth Harper clad in a Risky Business-esque button down "dress" and giving an occasionally overwrought, new wavy, pop-starlet shtick. The xx followed, suitably opening with "Intro." Fog machines cloaked the stage in a ghostly aura and multicolored strobes throbbed in time with the drumbeat. The light show was impressive; perhaps it was the nature of performing at a venue as large as Sonar, or something that the xx has crafted and perfected along the duration of their first American headlining tour. At times an eerie purple haze enveloped the band; other moments were marked by a stark contrast of darkness and intense illumination, adding to the tension of the band's emotional vocal delivery.The xx flowed effortlessly between songs and extended instrumental passages at the end of "Basic Space" and "Shelter" proved that while it's still young, the xx has learned quickly how to make a fan's dollar matter in the Great Recession economy. The band members had their signature, intense stoicism on display; relatively stationary and staring deeply into the distant horizon, expressionless and somber. Surprisingly enough however, the minor stage banter that did occur, coming solely from bassist Oliver Sims, was marked by his massive grin of gratitude and elation. He thanked the crowd profusely for welcoming them so warmly into the city on the band's first performance here with a genuine sense of sincerity and appreciation.After a cathartic and dramatic closing with Sims crashing wildly on a massive cymbal, the trio returned for an encore, playing standout track "Stars." Many of the sold-out crowd missed out on a hidden gem: in the club Room of Sonar, drum programmer Jamie xx and guitarist Romy Madley Craft took to the DJ booth to conduct the sweaty, inebriated assembly.Jamie flew wildly through tunes such as Deadboy's "If U Want Me," recently released on Glasgow's label/cartel Numbers. Scarcely letting one track settle into its groove, he still maintained a constant flow and narrative, much akin to his recent mix for Annie Mac of BBC Radio One. As Craft took over shortly after 1 a.m., the mood shifted toward R&B slow jams and southern hip-hop, including one stand out cut from DJ Drama's Gangsta Grillz series. The pleasant absurdity of a pale, jet black-clad English woman standing behind the DJ booth as "GANGSTER GRIZZILLZ" belted through the PA system made the additional $5 well worth it.