_substrate is a WebGL collaboration between musician/producer The Haxan Cloak, graphic designer Mathew Lucas, lead developer David Sweetman of Durham-based digital product agency Smashing Boxes and Moogfest. The responsive, interactive application allows users to control individual audio tracks from Moogfest 2016 participant The Haxan Cloak's remix of Moses Sumney's cover of Laurie Anderson's O Superman by swiping+tapping on mobile devices or utilizing the arrow keys+mouse on a desktop device. Each of the 8 audio layers has an accompanying WebGL visual rendering and responds with audio initiated by user action. _substrate is in fact a constant layer beneath the official Moogfest website http://moogfest.com running continuously on every single page, ready for play.