Did you know that a simple speaker completely transformed modern music festivals? A vertical line array is a loudspeaker system that stacks speakers on top of each other so that sound is more evenly distributed on a horizontal plane. To learn more about line array, WIRED spoke with sound engineer Dave Rat. Dave, who has provided audio for Coachella since 2001, breaks down exactly how these speakers work, and why modern music festivals sound so much better than they used to.