Right.
What Derek said....with some "variations on a theme" as it were.
Basically, what it comes down to is: if the director is clueless about
shooting these kinds of scenes....then you're fucked.
Kill yourself now...or better yet - kill the director. They're a dime a dozen...and no-one will miss him.
I can see this type of scene in my head...and it looks like the Blues Brothers...
In the ideal world, the band/choir performance will be
pre-recorded and played back on set. The band/choir mime to this.
This is the only way to get consistency of performance from shot to shot, and therefore the only way that the show will cut together with any degree of simplicity. Make sure that the playback gets printed to tape/Dat at the same time. The director needs to shoot the shit out of the band/choir dealie...ie get more shots/angles than he thinks he needs. Don't forget to record at least 1 complete pass of the track - this usually accompanies the master wideshot. Also, have a mic going with the camera on the close-up shots, so you can just grab a snare hit, or a vocal sound to reinforce the playback track when it comes to the final mix...y'know - that little bit of reality...
Once you've dealt with the band, the shoot the cast delivering their lines. This might involve the band/choir or the congregation being in shot. They need to be miming
silently so the cast can deliver the nuanced performance that the director wants. Make sure the congregation is silent too.
Any extraneous noise over this = ADR. ADR IMHO never quite captures the exact same performance...usually due to the passage of time from production to post-production.
Once the stars are done, do the crowd. Make specific recordings of any "group reactions" required - astonished gasps, cheers, boos, laughter, applause etc -
in that room. This is so important, because the CD sound effects never sound exactly like "your" room...
Then get the walla stuff. If you've got the gear and the time, get mono and stereo recordings of all the crowd stuff...It'll give you more options in post, and help better achieve that sense of reality within the film.
If you don't have the time/gear to get both mono and stereo, then get MONO. It'll help with the focus of the sound trackCheers,
Tim