I guess I'm confused now... this is for the recording of band/choir concerts, but you're looking to upgrade your 24
channel 8 bus to 32 or 40 channels, possibly digital
console. My question would be... what are you doing with all those channels? Seems you could go one of two ways with your recording philosophy based on your room & setup.
1) the room is built for the types of things you're doing - band & choir concerts - and things sound good on their own. The PA just provides reinforcement for announcements or something. That means you go with a few well-placed mics to
pick up the ambiance of the room, along with maybe a solo mic or two (or mic by sections whether choir or band or
orchestra) that you just
send to tracks to beef up your recording.
but if your room is more PA-centric...
2) You close-mic things because the room doesn't support these 'acoustic'/natural activities well, and you use your PA to reinforce the band/choir/
orchestra, and mic things accordingly. This is a very different setup & will require lots of mic'ing (with the according hardware, lines run, and expertise/experience).
I would argue if you're having to take the #2 approach, it would be worth considering just changing the room to fit the purpose. Of course, $7K won't get you very far into the possibility of changing room shape, seating areas, acoustical treatment,
etc
Either way I suppose you need a multitrack recording device. Your 8 bus appears to have balanced direct outs, you'll need a 24 ch TRS-TRS
snake to hook up an HD24 if you go that way.
Sending the multitrack (HD24 or not) back through the board for a remix is certainly easy, but to remix for broadcast it would be better to dedicate a listening space for this purpose instead of listening to the remix in the PA or
headphones (especially if your
system is more of the #1 style). Having a computer/DAW to remix the tracks on in a studio-type room (built & acoustically treated appropriately, with nearfield monitors,
etc) might be the best way to approach this.
-Blanton