It's no secret that homogenization in popular art is growing stronger with each corporate merger. But in truth, most acts who garner enough attention to have their grievances heard don't deviate enough from established forms to warrant the rendering of labels obsolete.

Enter Sigur Rós, the Icelandic quartet playing May 1 at the Marin Center and about whom it's safe to say that they will never be heard on mainstream American radio. Indeed, they remain the best argument yet for doing away with genres (and Westerners' attempts at pronunciation).

The band's unclassifiable, idiosyncratic style was evident from their debut album Von, which translates as "hope." "Sigur Rós" the song is a 10-minute ambient exploration in which screaming echoes swell and crash amid sparing percussion. Songs that follow exude everything from arena-ready hard rock ("Hún Jör") and jangly Johnny Marr-esque guitar-bounce ("Myrkur") to the sound-effect laden "Mistur." It's no wonder that halfway through the album appears "18 Sekúndur Fyrir Sólarupprás," an 18-second silence that serves as an intermission for the eccentric symphony.

Most recognizable is Jónsi Birgisson's soaring, falsetto voice, which--to American ears, at least--recalls Enya, of all people. His singing seems to hover in the background, blending with percussion and strings so whimsically that his vocals become just another instrument. Furthermore, Sigur Rós' lyrics are chiefly sung in "Hopelandic," an indecipherable language created by Birgisson to mimic Icelandic. But even when their lyrics are in their native tongue, they sound otherworldly, which makes their commercial success that much more fascinating. Sigur Rós' music amazingly shatters the language barrier, with sheer emotional resonance connecting with audiences in a major way--they're one of the headliners at this weekend's Coachella Festival down in Indio, Calif.

Acclaim for Sigur Rós spread steadily after the release of their second album, 1999's Agætis Byrjun ("an all right start"), which sold over 600,000 copies due mostly to word-of-mouth. Fans included rock innovators Radiohead. Undoubtedly, Thom Yorke and co. were influenced by Sigur Rós when making their divisive album Kid A, full of the same orchestral, cinematic soundscapes and lush, floating vocal refrains. Sigur Rós crept onto the mainstream radar, most notably with the rolling, gorgeous "Svefn g Englar" which appeared on the high profile Vanilla Sky soundtrack.

Their next album, 2002's ( ), was more cohesive and plaintive. With eight untitled tracks, a grammatical sign for an album title and a sparse white cover design, the release stripped away all artifice. By boldly rejecting all language, they forcibly challenged listeners to focus on the complex music itself. The band likes to think of their process as organic. "There is nothing clever about how we write songs," insists keyboardist Kjartan Sveinsson in the band's press materials. "It's just mucking about." Whether true or not, at least the song titles could be pronounced, arbitrarily named "Untitled" 1 through 8. One highlight is song number six, with its slow-rising pianos giving way to the epic, anthemic guitar chimes. (Coldplay are huge fans, demonstrated by a similar sonic ascension in "Fix You.")

According to the band, their most recent album, last year's Takk . . . is a "rock 'n' roll record." Although the description is a stretch, Takk . . . is their most musically accessible record to date--and their first sung entirely in Icelandic. The gorgeous, prominent piano lines and guitar chords actually sound familiar. The horns on "Hoppípolla" actually sound Beatlesque, and the symphonic backing and slow guitar strumming on "Andvari" wouldn't sound out of place on the Verve's Urban Hymns. The album's title, which translates to "thanks," is their most fitting yet, as they reward their adventurous supporters by meeting them halfway.

The band's live shows are just as hypnotic as their music, and have been known to inspire fainting among fans. The Marin Center's Veteran Auditorium is a symphony hall whose acoustics are perfect for Sigur Rós' atmospheric creations.

The accusation that Sigur Rós are pretentious is understandable but irrelevant. Their undeniably pleasing melodies make the term "avant-garde" appear superfluous. Perhaps Percy Bysshe Shelley got it right when he spoke of words losing their meaning, because the best way to describe Sigur Rós' music is sublime.

Sigur Rós perform on Monday, May 1, at the Marin Center. 10 Avenue of the Flags, San Rafael. 8pm. $50. Darn-near sold-out. 415.499.6800.

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