The Iceland Cometh to the Los Angeles Philharmonic these days, specifically in the form of what would seem an unlikely Reykjavík Festival, a wide ranging exploration of the contemporary music scene in the Nordic capital running April 1 to June 4. The offerings range from Bjork (in digital form) and Sigur Rós (live) to, well, a bunch of ostensibly classical composers you’ve never heard or heard of. Perhaps that’s the point: It’s time we did.

I ventured up to Disney Hall on Saturday night to hear a program dubbed “Sigur Rós III” that featured the artsy post-rock band in collaboration with the Philharmonic and none other than Esa-Pekka Salonen. The orchestra and Sigur Rós were basically doing their thing for the third night in a row, but the substantial prefatory material was different.

What a crazy and ingenious idea for a concert. The hall was filled with an unusually young and hipster crowd, Sigur Rós fans, make no mistake. Having this captive audience, the Philharmonic took a page from the Boston Pops, fiddled with it and performed a set of bristling Icelandic music — medicine, so to speak, to help the sugar go down. Judging from reactions, it seemed to work.

I was most curious to hear the Organ Concerto by Jon Leifs (1899-1968), one of the greatest Icelandic composers but rarely encountered on these shores. Leifs himself has an interesting story that I won’t get into here, but a highlight (or lowlight) of it involves this very concerto, performed in Nazi Germany by the Berlin Philharmonic in 1941. Leifs was living in Germany at the time, but this furiously dissonant concerto, written in 1930, put him permanently on the outs. He left for Sweden, with his Jewish wife, in 1944.

Leif’s concerto opens with a series of tone clusters blasted by the organ, vigorously answered by caustic brass and thundering timpani, an assault. A passacaglia (repeating bass line) ensues, all twelve chromatic tones in it, a glowering thing. There are 30 variations over the passacaglia theme, slowly building to a couple of ear shattering climaxes. The regularity of the bass line brings order to an otherwise cacophonous world. The coda arrives and Leifs uses it to reiterate cadential formulas, which seem to duke it out for a victory that never arrives.

The piece’s length — only 20 minutes — adds to the impression; the listener feels as if he’s been grabbed by the neck and given a good shaking. Organist James McVinnie played the solo as if he were Homer Simpson chowing down a meal (and he, unfortunately, did outgun the orchestra a little too often) and Salonen and the orchestra answered in kind. Somehow, it was great fun.

The concert opened with Leifs as well, a brief a cappella Requiem (vacillating suddenly between major and minor, drone-filled) sung by the 18 singers of Schola Cantorum Reykjavik, led by Hördur Askelsson. At least I’m pretty sure it was the Requiem. The house was too dark to follow the words and the program listed five pieces to be performed by the Schola, but only four were. At any rate, it’s a tight, well balanced group, and the other generally folksy pieces were a delight as well.

Salonen then led the U.S. premiere of Maria Huld Markan Sigfúsdóttir’s “Aequora,” a pretty and sparkling soundscape (no faint praise implied) that sounded as if it were a mash-up of the beginnings of Mahler’s First and Strauss’s “Alpine” symphonies with the Prelude to Act I of “Lohengrin” thrown in.

It served as a fitting intro to the spacious world of Sigur Rós, though the organ concerto and intermission came first. Sigur Rós, now a trio, performed a set of songs with the orchestra, the arrangements by the likes of David Lang, Nico Muhly and Missy Mazzoli (real classical guys, in other words). In the heavily amplified sound environment these arrangements seemed no great shakes, mostly just the typical symphonic filling out that orchestras are called to do for rock bands, though tasteful in this case. Salonen waved his arms efficiently, and exacted detail when necessary (which was occasionally).

Sigur Rós did its thing, which sounded like the music you might listen to in an isolation tank in rotation with the calls of humpback whales. One song sounded like the theme to “Mystery Science Theater 3000” (the version at the end of the show) slowed down for the sake of profundity. From what I understood (which was nothing) everything was sung in either Icelandic or a made up language called Vonlenska, which is like Klingon on sedatives. No texts were provided.

In other words, it wasn’t so bad if you like this sort of thing. Salonen and the L.A. Phil then took off, so did I, and Sigur Rós and fans stayed for another set. They may still be there now. I really do like the idea of a symphony orchestra opening for a rock band, though.