No translation necessary

There are advantages to singing in a language of your own invention. For one thing, if you blow a lyric during a show, who’s going to know? You’re also immune to critical carping about not making sense or being cliched. And these days you’re not even isolating yourself in a remote corner, not when there’s a substantial audience in the U.S. that enjoys music sung in strange tongues -- Salif Keita in Malinke, Nusrat Fateh Ali Khan in Urdu, Bob Dylan in English.

That crowd, crossing art-rock, world-music, trance-dance college-rock and exotica borders, filled the Wiltern on Tuesday to bask in the enveloping sound of the Icelandic quartet Sigur Ros. And singer Jon Thor Birgisson certainly didn’t need recognizable words to connect with his listeners on the first of the band’s two nights at the theater.

The message was entirely in the gripping urgency of his unique singing -- a sharp, intense keening that resides at the outer edge of the vocal atmosphere. Sometimes his syllables almost sounded like something familiar -- “inside” or “you slide,” “Yes I ... I’m down,” “shine on our fire” -- but essentially they functioned as a sort of celestial, slow-motion mantra.

It was the focus of a series of grand musical tableaux, several of them drawn from the group’s recently released second U.S. album, whose title is a symbol that looks like a set of parentheses and whose songs have no titles at all. (That’s one way to discourage audience requests; no one shouted “Track 5!” Tuesday.)

Nearly two hours of this can be demanding, but the tendency of the mind to wander (or shut down entirely) diminished as the pace and power gradually picked up. Commentaries about Sigur Ros invariably cite the sound as a reflection of the rugged, mysterious beauty of their homeland, and while that might be a stretch, you certainly wouldn’t say the Bahamas if asked to guess where this music originates.

Most of the pieces began with a stately motif, often from Kjartan Sveinsson’s piano or Georg Holm’s bass, then grew inexorably in density and intensity. Birgisson played his guitar with a bow most of the time, thickening the brew, and at one point he held the guitar in front of his face and sang directly into the instrument’s electric pickups.

Holm created sonic clouds by strumming chords on his bass, and on one song he tapped out a riff on his strings with a drumstick, leading into an almost bouncy song reminiscent of Peter Gabriel. A four-woman string ensemble called Amina added to the texture, and drummer Orri Pall Dyrason pummeled like a rocker, sometimes leading the band into a fearsomely prodigious attack.

The closest comparison in mainstream rock might be Radiohead, whose endorsement helped bring the group into the non-frozen world a couple of years ago. The outline of that emergence might sound arbitrary, the product of some lucky connections, but Sigur Ros’ performance argued that anything this doggedly original and powerful would inevitably find its following, far and wide.