The Skyline Stage at the Mann Center for the Performing Arts could hardly have made a more stunning debut then it did on Sunday, when Icelandic ambient experimental ensemble Sigur Ros opened its U.S. tour with the first show of a sold-out two-night stand.

With the moon peeking through the clouds and, yes, the Philadelphia skyline visible through the trees on a balmy summer night, Sigur Ros - whose four main members are bassist Georg Holm, guitarist Kjartan Sveinsson, drummer Ori Pall Dyrason and singer-guitarist Jon Por Birgisson, known to the world as Jonsi - was making its first appearance anywhere since 2008.

That would have qualified the appearance in support of its sixth album Valtari by the band - whose core quartet was augmented by seven musicians, including trios of string and horn players - as an event, even if it did not inaugurate an idyllic new concert space that puts a 4,000-capacity field at the top of the Mann's grounds in Fairmount Park to creative use.

Front man Jonsi wore a fringed-sleeve jacket as he played his electric guitar with a cellist's bow and sang in a soaring falsetto that lifted the music toward the heavens, even when, on songs like Valtari's "Varuo," the ethereal quality that makes the group's sound so distinct was harnessed to a muscular propulsion that served as a reminder that Sigur Ros is, among other things, a rock band.

As Sigur Ros albums go, Valtari is a bit sleepier than most, and while its infinitely patient arrangements aren't always altogether gripping, it still qualifies as Sunday morning music of the highest order. And on a Sunday evening, with the added oomph resulting from a group of sterling musicians performing in front of a pumped up, ready to have its collective mind blown crowd, songs like the glitchy "Ekki Mukk" and diaphanous "Dauoalogn" came vividly to life.

Sigur Ros don't sound like anyone else in the world, but its luxuriously precise atmospherics are part of an independent spirited art-rock continuum that reaches back to the Cocteau Twins in the 1980s and on to contemporary fellow travelers like Radiohead and Bon Iver.

And even though the band has been making music for a decade and a half, there's still a strangeness to Sigur Ros' otherworldly music that is part of what makes it so transporting. At the Mann, Jonsi did manage a few words in English: "This is our first show in four years. We are really enjoying ourselves. Thanks for coming."

When he sang, however, it was either in Icelandic or Vonlenska, the made-up gibberish also known as "Hopelandic" whose meaning is known only to him. The oddity of his enigmatic enunciations added to the aura of mystery, as the arrangements moved from interludes suited to contemplative introspection to fanfares of emotional catharsis.

Sample conversation at a Sigur Ros show: "Do you know what this song is called?," asks the critic with notebook. "No," answers the smiling man singing along to syllables that have no meaning to him. "But I love it."

Seattle pianist and songwriter Mike Hadreas - who performs as Perfume Genius - was well worth arriving on time for. Was that a languorously intoxicating version of Neil Young's "Helpless" he was playing as concertgoers made their way up the hill to the Skyline Stage, which is located off North George Hill Drive, behind the Mann's amphitheater's lawn seating area? Yes, it was. Hadreas highlights also included "Hood" from his 2012 album Put Your Back N 2 It, and a quietly powerful cover of Madonna's "Oh Father."

Contact Dan DeLuca at 215-854-5628 or, or follow on Twitter @delucadan. Read his blog, "In the Mix," at