I have produced over 5 Cds will some very nice results...
Make a Deca Tree, 3 microphone arrangement;

try to rent some additonal mics, because it is always safe to have some spot mics even if ya do no use it at the mixing stage

I would go for:
a) main Stereo L
b) main Stereo R (here,both over conductor´s head, let us say 2.5 meters)
c) nice condenser for the Violas section
d) 2 nice condensers for the stereo piano
e) a beta 57 can do a goo job to an acoustic bass
f) additional percussion shall be picked with a micrphone per drum, like snare, cymbals and so
g) equalize as little as possible and do not force too muh into gai. If your board is really fancy oka, but sometimes if ya pick a behringeror some other cheap console, things can become noisy
h) do not compress or just compress as little as possible. Rember, this album is not to beat Top 10 MTV or BillBoard. You go for real dynamics. If not they ould rent some samplers and do the trick.
There are some nice and other hated mics that can do a nice job like At4050, GT55, C300B, C2000B, Sm81, Beta57, Sm91 and Avlex cheap stuff.

Hope it helped ya
Alécio

Hi

I've been involved in orchestra recording several times (location and classical recording are my main gigs), and there's several ways to do it: first thing you have to know that recording an orchestra can be at the same time extremely simple and incredibly complex, depending on how many and what tipe of mics you use and how you place them. Provided that you're in a good sounding room or hall the simplest approach is to use a main stereo pair over the director's head a few feet back and 8 to 12 feet tall; stereo techniques for this purpose can be diverse and each one has it's own sound and stereo image: MS, XY, ORTF, Decca tree are the most common and tend to give the best results (although many recordists experiment and find variations on these with excellent results). This main OH pair should cover the whole orchestra area (with Decca tree using 3 mics and MS being decoded to 3 signals), and you should use it to get the most sound from it: one school of thought actually uses only that and no other mics. Spot mics are used closer to the sections or in some case on each instrument to get more focus, reinforce the stereo image and to fix things if necessary.

In your case I would go with the main stereo mic (what kind of mic is it? what pattern?) placed as above, using the second stereo mic farther back in the hall to get the room sound (whatch out for phase issues), and I'd try to rent some more condenser mics for spot on sections and instruments: at least one for 1st violins (small dia KM184, AKG 451, Audix SCX1, Schoepps CMC5, B&K), 1 for violas (small dia, same as violins), 1 for cellos (large dia, U87, AKG 414, AT4033, 4050 or 3035, Audix CX111), 1 for double basses (large dia, same as cellos), and 1 for each brass or wodwinds sections. If you have dynamic mics you should have percussion covered, even though I like to use condensers on those too. You may ask why so many mics? Because if it's the first time you attempt such a "colossal" task as recording an orchestra where mic placement and selection are critical, chances are your main stereo pair will need some help from the spots so you'd want to have that covered (just in case), and shouldn't that be needed you could always use them for creative purposes.
You could create an instant mix of all of the sources and go 2track on the recorder or if you have a multitrack recorder print each mic on a separate track and work afterwards in mixdown. Another word must be spent on preamps: what will you be using? how many channels? Be sure to get low noise and the least colored preamps you can so as not to mess with the sound in the first place; try to put them in the hall with the players, so that the cable runs from the mics are shorter and let the line level cables from the preamp to the monitoring/recorders travel the longer way: this will make for a clearer less prone to noise signal. If you will be monitoring on headphones be sure to know them well, so that you get a reasonable picture of what you're recording, though I always prefer to bring a set of powered monitors and set up in a separate room.
Try to record rehearsals too, so as to have more material to edit and as a backup in case something goes wrong in the main recording. What format will you be using for recording?
Bring enough tapes or drive space to be covered for eventual encores and such. I usually run a 2 track mix on DAT alongside my multitrack recorder so as to have a reference for the director and a safety backup. Keep notes of everything, from your busing/patching of mics and preamp channels to choughs in the audience.
It seems difficult (and it is) but if you follow some basic rules and most important take the time to find the right placement for the mics it will work OK.

There's lots more to know, it takes years of practice and dedication (I still assist some major engineers sometimes to learn their techniques and tricks), but I hope these simple guidelines will be helpful.

Good luck and have fun. :)

Wow! Thanks for all the input. I'm really excited now. I'll have to try the things suggested and let you know how it comes out. The main thing is going to be that we are on a low budget, and while all the things suggested are great, some of them require equipment (to put it in the vernacular) we ain't got. The condenser mics we have are three high-end AKGs, a possible fourth tube mic, and two Sony MS907 stereo mics. There is a definite possibility of getting more, and I think we'll have to do that. We're going straight into a Mackie 16-channel mixer and will be recording to an Alesis ADAT. Well, anyway I have to run, but I wanted to say thanks, again, and I'll definitely try what you suggested. Take care.

Mike