The stadium next the Sant Jordi is the Olympic stadium, and nobody plays there. While th RCD Espanyol football team was building their new stadium they played their home games there, but since they moved to their new stadium, nobody plays there, besides some American football games from time to time and big concerts like U2, Bruce Springsteen, acdc etc
Palau Sant Jordi is a tricky place because of the acoustics. I attended there many concerts and they usually sounds well. I saw MK there I think two times with the stage at the middle of the arena and the sound wasn't bad considering half venue was empty behind the stage and the sound was being loose through the Dome...