Recording an audience
 

I have been asked to film a dance concert in a couple of month’s time; I have all the video side sorted. However, I am planning to do a separate audio recording and am not sure what microphones I need. The concert is in a 1200 seat theatre. Has anyone done this sort of thing before? What mic’s do I need, where do I put them?

well ive never done it for the audience but i have done it for a choir (so just pointing the other way really)

Ideally 2, 3 or 4 booms (depending on stage width) mounted on a lighting truss at the front of the stage , pointing at the crowd would be my way to go if possible, even 1 boom up high will give you better results as trying to do anything at ground level might mean picking up conversations or sweet (candy) wrappers from those nearest you, ideally you want to be up and away to pick up general noise rather than just those closest to you

This is what I use for a 2000+ seat theatre when I do Outside Broadcasts and possibly a bit to complex for your situation...
Cross pair of 416 shotgun mics about 1/3 down the theatre from the stage and about 2-3m high,
The other side of the theatre about same position and height a good stereo mic (Shure VP88 or AKG C522 or Rode NT4).
And on the first balcony 2 omni lapel mics about 2-3m apart taped on the front of the hand rail.

I'm working on layering the sound with a very full open theatre from the omnis to smaller groups of people 50+ with the stereo mic and to very small groups 10+ with the 416's.
Its quite often a good idea to sit in a crowd.. close your eyes and listen to the sound around you and work out how to create this with mics.

But in your case make sure any mics you use face AWAY from the speaker stacks....

A lot of live performance auditoriums already have audience microphones mounted from the ceiling. I'd check that out first and see if they'll let you you tap in. If no to that angle, then short shotguns mounted just offstage, aimed at the audience should do. I don't think more than two would be needed. In small clubs for musical performances, some people use PCMs mounted high up on a wall or hanging off the ceiling.

Here's what Schoeps has to say on the subject. These microphone configurations are typically used to record the music on stage. Placing the mics is a matter of taste and logistics -- what will hall management let you do?