This is something that's been a question of mine since I started listening to live recordings of bands: why don't you hear the pyrotechnics on the recording? On officially released recordings, ok, there are good reasons for every band this side of KISS to edit the bangs out, but even on bootleg tapes made with handheld recorders, the explosions rarely register. With as loud as those things are, I'd expect them to cause massive distortion--so why don't they show up at all most of the time?
Microphones are designed to pickup certain frequencies. Now if you were using a Shure Beta 52, those explosions would come out nice and clear. But everything else would sound like it's in a pillowcase. If you're using a "built-in" mic, you're only gonna get certain frequencies that it was designed to pickup.