How should I mike a choir for PA or recording?

I need some help miking a choir. I'll have 3 rows with 15-20 singers on each row.
Bob Turnbow.

Reply: We recommend using two Crown CM-700 cardioid condenser mics for a temporary setup (recording or PA), or two Crown CM-30 or CM-31 hanging mics for a permanent PA setup. The CM-30 electronics mount in an electrical outlet box in the ceiling. The CM-31 electronics are in an XLR connector.

Please see the diagram below. Divide the choir in thirds left-to-right with the two mics.

For PA, place the mics 1.5 feet over the head height of the back row, and 1.5 feet in front of the front row. That close placement will result in good gain-before-feedback.

For recording where you want to pick up the room acoustics, place the mics 3 feet apart on two mic stands, or place them on a stereo mic adapter on top of a single mic stand, angled 90 degrees apart and spaced 11 inches apart horizontally. Start with the mic stand 12 feet from the choir, with the mics as high as possible (about 1.5 feet over the head height of the back row).

Monitor the choir pickup. If the sound is too close, detailed, and dry (lacking hall acoustics), move the mic stand a few feet farther from the choir and listen again. If the sound is too distant, muddy, and reverberant, move the mic stand a few feet closer to the choir and listen again. Eventually you'll find a sweet spot with a pleasant amount of room acoustics, but not too much.

If you use omnidirectional mics, you'll need to place them closer to the choir than you place cardioid mics in order to get the same amount of hall acoustics in your recording.