When you start talking about live, loud, rock concerts, you start talking about Sound Pressure Levels (SPL) in excess of 120 - 130 db. There's no reasonable excuse to build a mic capable of handling those kinds of levels into a cell phone. Most phone mics will simply hit the wall and distort like crazy. I've even see this happen with dedicated, high end audio gear. The mics that came with my MiniDisc recorder were not capable of handling it. The twin condensers in my Tascam DR-40 might have a slight problem if the band was super loud and I was close to the PA system. That's why the mics I use on stage for high impact instruments (bass drum, bass, electric guitar) cost more than a Galaxy S4. Also... the acoustics in most arenas aren't great. The further away from the sound system you get, the muddier the sound tends to be.