Messy/ Bad Audio Quality

Okay, so about a week ago, I went to this concert and recorded it with my galaxy nexus phone. I went home and checked the videos only to find out that the audio quality was ****! The electric guitar and bass sounded very messy and all over the place, and it was overlapping the voices of the singers. It makes this kind of buzzing sound whenever the instruments are played. I've tried using equalizers but it made no difference. How do I fix this?