On July 8th, Skrillex will head out on his second Full Flex Express Tour through Canada. The tour, which will travel through eight cities by train, is headlined by Jack Ü, his duo with Diplo, with support from A$AP Ferg, Zeds Dead, Kiesza and others. Like the first Full Flex Express Tour in 2012, it's an EDM tribute of sorts to the original Festival Express train tour, which was headlined by the Grateful Dead, the Band and Janis Joplin back in 1970. 

Skrillex called a few weeks before the tour's kickoff to take part in Rolling Stone's Expert Opinion column. Here's a lightly edited transcript of his thoughts on the nine old and new songs we asked him to check out.