For the second spring edition of Outline, post-rock titans Explosions in the Sky headline. One of the key groups to define massive, crescendoing rock in the '00s, EITS writes, in their own words, "cathartic mini symphonies." They deliver a sense of scale and depth to the stage that few touring bands can match. Iceland's múm plays a rare set. The beloved electronic-pop group brings a rare intimacy and power to a sonic palette often described as twee, writing songs with a delicate sincerity and sense of easy play that is truly captivating. Guatemalan composer and cellist Mabe Fratti fuses breezy prog decadence and fleet-footed jazzy flourishes with crushing, stoner rock power. Philadelphia's They Are Gutting a Body of Water channels thick, noisy indie music with an immaculate sensibility. Dutch artist upsammy, best known as a DJ, performs live. Her music is restlessly inventive, folding IDM, bass music, techno and folktronica into something singular. Finally, Mexico's Diles Que No Me Maten imbues a heartfelt swagger and woozy grandeur into their sprawling, modern post-punk. Knockdown Center 21+