Big Sean, Machine Gun Kelly Rocked L.A. at Pandora's 'Sounds Like You: Summer' ConcertBig Sean, Machine Gun Kelly Rocked L.A. at Pandora's 'Sounds Like You: Summer' ConcertHosted by Kat Graham, a slew of fresh new artists took the stage at the L.A. Memorial Coliseum.CC RobersonCC Roberson