Renee McMahonBig Sean’s peach-fuzzed posse. Bumbershoot always attracts a lot of young festival-goers, but the crowd at the Main Stage Sunday night seemed to be almost entirely under the age of 21. After an awesome set by Deep Sea Diver, I followed the steady stream of teenagers into Key Arena to see if Detroit rapper Big Sean was any good live. Surprisingly, he was. The guy’s got swagger. Even from the farthest corner of the arena I could see him dance around the stage, taking pictures with the crowd and throwing out beach balls as he yelled, “I want y’all to play with my balls.” The crowd was on their feet bumping and grinding through the whole set, even up in the cheap seats. As I took notes on my phone the guy next to me leaned over and said, “You gotta get more hyped for this.” Slightly embarrassed by the call-out, I got up and danced as Big Sean blazed through the smash hit “A$$ A$$ A$$.” Renee McMahonMac Miller played Bumbershoot’s Mainstage on Sunday, September2.The arena was still buzzing with energy when Mac Miller took the stage. Squinting at the crowd with a lazy grin on his face, Miller looked almost as stoned as the teenagers in front (and behind) me passing around a pipe. After opening with a couple favorites like “Knock Knock” Miller moved on to a few tracks off his latest album, Blue Slide Park. Or at least I think he did. Between the crappy acoustics in Key Arena and Miller yelling too loudly into the mike it was hard to tell what he was rapping. As the set wore on, the audience’s energy level slowly slipped away. But Miller managed to get the crowd hyped again when he closed with “Donald Trump.” Sleepy fans got to their feet, putting their last bit of energy into singing along to Miller’s biggest hit before heading home for the night.