According to this reviewer, the audio on the Blu-Ray:
Sigur Rós, live, mixed in 5.1 and presented via a lossless DTS-HD Master Audio track? Yes, please, and thank you. Inni’s stellar visuals are backed up by an extremely powerful, immersive reproduction of the band’s nine-song set. If you’re familiar with Sigur Rós, you know that dynamic doesn’t even begin to describe the depth of their music, which combines deep bass, aching-glacier guitar swells, and crashing drums with crystalline high-end sounds like xylophones and tinkling electronics. Not to mention Jónsi’s world-shattering falsetto. Live, their sound is cavernously huge, drenched in watery reverb. This mix gets it perfect. Period. All 5.1 channels are utilized throughout, filling the room with rich, clear, forceful audio. You’ll want turn your receiver up loud, sit back, and soak it all in.