Last Saturday I attended the inaugural Breakaway Music Festival, a one-day fest targeted at college students, held in a modest soccer stadium in Columbus, Ohio. Headliners included Bassnectar, Empire Of The Sun and Kendrick Lamar, with Juicy J, Porter Robinson and Schoolboy Q among those filling out the bill. Also in the lineup was the charming B-list Toronto indie band Tokyo Police Club, the lone act among Breakaway’s 26 performers that could qualify as a guitar-driven rock band — and even they’re defined just as much by their keyboard parts and their rhythm section. Empire Of The Sun and fellow Aussies Alpine could technically qualify as indie rock, but their airy, synth-driven pop concoctions aren’t exactly heavy on the six-string action. Kendrick Lamar brought a live band with him, but only to perform in that jazzy late-night-TV style rappers sometimes adopt as a status symbol. Twenty One Pilots, one of the main-stage acts, signed to the pop-punk label Fueled By Ramen on the strength of a huge grassroots teenage/collegiate fan base but seems to have made a concerted effort to exclude the guitar from its schizoid genre mash, instead gravitating toward synthetic pop sounds like labelmates Paramore and Fall Out Boy before them.