Off-topic? Naahhh. I think this is a pretty good topic for the forum, because it really deals in a very basic way with the differences between LD and SD designs. I'm hoping Harvey will see this and chime in, because I'd *really* like to learn some more of what he knows about this particular application!
You'll probably find the C4s to be very useful- I don't know much about them, other than the fact that they are small-diaphragm. For large group recording like this, I'll always favor SD condensors over pretty much any LD design. The reason for that is simple: most LD condensors sound funny off axis. Their polar patterns are wierd *by design*, with spikes here and suckouts there, so that you can get completely different sounds by just changing the axis of the mic with respect to the sound source. This is *great* with a point source, but not as great with a distributed source like a large chorus: some fraction of the chorus will always be standing in a suckout, and if you have a powerful tenor standing in a spike location it'll just take the paint off the walls: all the director's careful vocal placement goes right out the window. It's really hard to get a consistently-usable sound with LDs for big groups, like the 150 voices that make up Skyline.
The TLM103s are just about the best affordable LD design for smoothness and consistency off-axis, which is why I like them in a pair for doing a quartet. They have a very nice top end that seems to complement most female barbershop voices, and no really big spikes or suckouts to piss you off. I also have a pair of Rode NT2s, and it's kind of funny to try to use them for the same application: they have a midrange suckout at about 45deg off-axis that makes the baritone just disappear, if they are standing in the wrong orientation- or to hear the bari appear and disappear as they move around during the song. *Aggravating*. No way I'd try to use those for a chorus...
So when it is time to do a chorus, I use Oktava MC012s. I always seem to err on the side of conservative, so I'll hang 4 or 6 of them as essentially section overheads, and I'll hang another pair set up as an ORTF pair about 2 feet behind the director, and about 4 feet over their head. In a good room, the mix usually ends up being 90% that ORTF pair, with just enough of the section mics pulled in to add some crispness to the articulation (and get those great ballad-breath inhalation sounds before the tune starts!).
I used to do the ORTF pair just as a safety (and track it to a different recorder) so that if something died, I'd get _something_ out of the session. But I always seem to end up going back to it as the main track. It's amazing to watch how a good chorus director reacts to the sound of that pair, because that very closely approximates what they were hearing during the take. At mix time I'll often submix the overheads to a pair of faders, and label them "body", route the ORTF pair to a a pair of faders and label them "air", and then just let the director play around until they get exactly what they like. It's consistent as heck, even with directors who aren't recording-techie types: they'll always trade off body for air... Let them experiment, and you can learn _volumes_ by watching: they know exactly what they want to hear.
For any of this, though, the room is absolutely crucial. You can't get a good sound in a bad room, and no amount of knobtwisting can help it. The ideal setup is to get into a good sounding room, put the mics where they sound good, track them flat, mix them flat, and print it! In a good room, all you have to do is the old Hippocratic thing: "do no harm". In a bad room, it's just not going to happen... Usually, the performance suffers as well, because the room ambience is critical for barbershoppers to be able to tune properly. The tuning parts (bari and tenor) have _got_ to be able to fit themselves into the sound, and if they can't hear properly, it's just downright tragic.
The 012s are very useful for live work with these groups, as well. Skyline does a Christmas show every year with a local 7-piece Dixieland band, and they do one tune together. Trying to get the chorus to balance with the trumpet, bone, and tuba honking along is a pretty good challenge... For that, I hang my usual section overheads, but I use the hypercardioid capsules, angled away from the center of the stage where the band is. That lets me grab the chorus and pull them up a tad bit without blasting even more of the instrumentalists into the room... Good fun.
Hey, Harvey (and any of you other good knowledgeable types): let's hear more!
