Did you try to record a rock concert from the audience? The problem with those is the bass notes overload the mic, the preamp channel or both. There isn't any quality back there to reveal. While the bass note is overloading, all the other notes and instruments vanish. So when you do pull the bass out of the show, there's nothing left but the damaged holes. No guitar no drums no voices.
There are ways to do those. From the audience, too, but you need a dynamic (moving coil) microphone...http://www.sweetwater.com/store/detail/SM58/
.. at least one microphone attenuator such as these.http://www.sweetwater.com/store/detail/IMPpad10/http://www.sweetwater.com/store/detail/IMPpad30/
And, of course, a field pro sound mixer.http://www.sweetwater.com/store/detail/MixPre-D/