Saturday evening began with the digital dub attack of Major Lazer, a computerized dancehall project of Diplo -- marking a return to Pitchfork -- and Switch. For an hour they assaulted the adoring crowd with very little music, mostly just bleats and blasts that sound like various industrial park alarms. The noises dodged and moved -- a frenetic mess for the ADHD set -- and Diplo spent most of his stage time shouting the name Major Lazer (at least four dozen times) and begging the crowd for hands in the air.

Big Boi doesn't have to beg.

Strutting on stage with one of his Atlanta MCs, the other half of hip-hop's acclaimed Outkast starting flinging syllables, eventually firing fastfastfast through "Ghetto Musick" over a machine-gun beat. A relentless hourlong set featured several Outkast hits (a snappy run through "Ms. Jackson") and a few guests, ranging from guest singer Neil Garrard for the tuneful "Follow Us" to a trash-talking youngster. The set dragged on and the beats became monotonous, but when he launched into "ATLiens" and hollered, "Put your hands in the air!" it was superfluous. They'd been up for a while.