I used to record choirs for provincial music festival competitions that were held in a barn style church with 45 ft ceilings.

I'd never recorded choirs but when the opportunity came up I went for it. It was interesting and fun! I did it for quite a few years and really enjoyed it.

I needed to keep it simple, the sound had to be pretty high quality and definitely accurate sounding for all the choirs being recorded and adjudicated. After all, these recordings where sent to adjudicators to be judged.

There were numerous children, men, women and mixed groups.

To keep the process simple I used a big boom that stood behind the choir director(s) that lifted up about 4m reaching out into the choir until the blumleim pattern reached the edges of the choir, yet sounded even enough in the middle so they could all be heard. The challenge was not all choirs stood in the same spots or height and I didn't have time to adjust between groups.

I ended up using a beautiful Royer SF-24. The tracks sounded great but my own preference would be a sound with less room and more choir, where I could blend my own Bricasti reverb to taste rather than keeping the traditional colder open church sound that it had. I know many classical performances and performers like that open sound so I respect that and refrained trying to mess with the organic sound it was.

If I had it to do over again I would try to get less room sound and a more focus that sounded closer but I didn't know how to do that without the mics being visually in the way.

Recording organs sounds fun! There are lots of threads here about choirs and organs that might give you some ideas too.

I'm excited to hear what you come up with.

As a simple rule, use either both condensers or both ribbons for microphones in a Blumlein or in an M-S configuration. With care, you can mix moving-coil dynamics with condensers (pressure-sensitive), but never fig-8 ribbons (velocity-sensitive). Note that multi-pattern condensers switched to fig-8 are still pressure-sensitive and so can form the S channel with a cardioid condenser as the M channel.

This is from a 2018 post on these forums:

The important thing that even some professionals get wrong is that you can't mix velocity-sensitive and pressure-sensitive types of microphones. This is because the decoding goes wrong due to the 90 degree phase difference between the two transducer types.

That is news to me, so most appreciated. I've spent the morning making up a bracket to allow me to mount 4 mics on on single stand - it's sort of working - I'll go with the 87/103 for the M/S. Thanks. 

I got it done. Not listened yet, but at the end when I was deriving, a chap came over and asked me why one of the microphones appeared to be facing sideways! I’ve got two more prospective jobs too. However next weeks recording at the same church is going to be tricky in the extreme. The 6 singers are in the altar area, past the choir stalls at some points, then walk to the bell tower at the other end, using centre aisle AND side aisles, splitting into 3 pairs. Then the go from the reverberant church acoustic to a much deader sound under the tower. A few ideas just wont work because of cable issues. I’ve paced it out but I reckon I’ll need to make up at least a couple of 50m cables. I’m thinking the only way to cover the space could be spaced omnis and try to blend these together to make the source do the split up thing? Even concepts like left right and forward and backward might be wrong. How about M/S facing across from half way down? Then altar would be far left, tower far right, but what would happen as they walk between? Aaaaaaagh.

I’m trying to meet a deadline, so the video should be possible shortly, but here are a few pre-video thoughts. The church, though big, was not overly reverberant, so for the actual recording for the choir, I’ll add some gentle artificial reverb. In the rehearsal, the X/Y setup with the AKG414s was a little dead, so I changed the mode to fig-8 and recorded in Blumlein, but there was an unexpected downside when listening* to the tracks. It has captured the space better, but it also captured far more audience sound, and I had a couple of text notification sounds right in the silence between sections and coughs, sniffs, throat clearing. Foot tapping and general noise. The old fashioned A/B system, actually did pretty, reducing audience noise. M/S was actually quite good, but again, picked up lots of audience noise. If it was a recording with no audience then I’d go Blumlein. M/S with the ability to set the width back in the studio is neat.

in the video I might be able to show the difference in the stereo field if I record the screen capture? I think I’ll have to explain stereo mic techniques though?