Explanations abound for the existence of the Olivia Tremor Control's Explanation II: Instrumental Themes and Dream Sequences. Originally packaged as a bonus disc with the band's debut album, Dusk at Cubist Castle, Explanation II was subsequently released as its own album by Flydaddy. The music is almost a complete 180 degrees from what is featured on Dusk at Cubist Castle. Where that album is comprised of hyperactive Brian Wilson/George Martin-inspired sound collages, Explanation II is a disc of warm and calm ambient music. Apparently recorded on the back porch of the band's house in Athens, GA, it is entirely unclear what instruments appear on the disc. Parts sound like they may have been created by gently controlled guitar feedback, organs, chimes, and tastefully played clarinet. There is plenty of real ambience on the disc, too: Crickets chirp, dogs bark, and a thunderstorm rolls in from the distance. It is beautiful, soothing music. It has been said that one is supposed to play the disc simultaneously with Dusk at Cubist Castle to create quadraphonic sound, though that is unlikely since the albums are of different lengths.