Post-rock, by nature, is a genre of rule-benders. It caters in textures and ambiance, appropriating conventional instruments in unconventional ways. It’s the David Lynch of music genres, determined to create a cohesive aesthetic while damming traditional narrative structure. Just shy of 35 minutes, Caspian’s live debut isn’t so much an album as one extended scene. Here we’re given five tracks, plucked equitably from the three studio albums that comprise Caspian’s five-year career, arranged in troughs and heights to create a wave of sonic activity, then played live on a specific night (October 22, 2010) to a specific space (a lofty Boston, MA, church) chosen specifically for its unique acoustic and aesthetic composition.
 
The aesthetic story that Caspian tells here crescendos and decrescendos through two modes: 1) vast fields of isolated notes that build as if emerging from foggy water and 2) thundering layers of four guitars tremolo picking to chilling, ethereal heights. Opening and middle tracks “Last Rites,” “The Dove” and “Concrescence” serve chiefly to widen the gap between the engulfing sonic eruptions on “ASA” and closer “Sycamore” to prolong a tension that makes the explosive battery of guitar all the more visceral and invasive. Things get most metal for the album’s final 10-minute stretch (a lengthened version of Tertia’s “Sycamore”), when the first power chords break violently through the sustained haze of lonely notes, and drummer Joe Vickers vaults into beatdown mode, as if some kindly Old South Church parishioner just offered him a Red Bull spiked with Holy Spirit and PCP.
 
On any live album, especially one without any vocalists to “totally screw up a great song” through warped delivery, the only choice worth criticizing is song selection. Caspian could’ve pulled more head-bangers from The Four Trees, sure, but in doing so would have compromised the gentle rise/ravishing climax the band so carefully cultivated with these five tracks.