So Percussion (often styled Sō Percussion) is an American percussion quartet based in New York City. Composed of Josh Quillen, Adam Sliwinski, Jason Treuting, and Eric Cha-Beach, the group is well known for recording and touring internationally and for its work with composers such as Steve Reich, David Lang, Paul Lansky, Steven Mackey, Bryce Dessner, Fred Frith, Dan Trueman, Tristan Perich, Martin Bresnick, Oscar Bettison, Evan Ziporyn, and Arvo Pärt. Originally formed when the members were students of Robert van Sice at the Yale School of Music, the group also continues to play works from the standard repertoire of percussion ensemble music—including works by composers such as John Cage, George Crumb, and Iannis Xenakis. In addition to their work with composers, the members of So Percussi