Q: I can't get in the studio with my band, so I'm sending them the individual instrument parts to record themselves, in their homes. Guitar and bass and keys can record through an interface, but I don't know how to get quality audio from the acoustic instruments. (For most of them, the only mic around is in their phone) How can we get clean takes from that kind of limited setup?
A: what stands out more to me in this situation are not concerns of acoustics, but concerns of how the band plays together (or, how to effectively simulate the phenomenon of the band actually playing together). one thing i will suggest is to do the drums first, so everyone else can hear the drums. that's just for the sake of the chemistry and the quality of everyone playing together. Actually, what i would really recommend is, after doing the drums first, send it to the chordal instruments, then send it to vocals, then send it to bass, then send it back to the drummer with drums muted and a very strong click (oh i forgot to mention you absolutely must have the click in there from the start), then send it back to the chordal instrument(s) and have them re-do that, with the new drums included, then maybe send it to bass to have that redone, then back to vocals, keep going around like this and have the people re-do their parts each time, because each time it gets closer and closer to creating the illusion of people actually playing together, because now they are hearing each other... even better, they are hearing each other do what they did while hearing each other. but i just realized you probably already knew all this. but as far as acoustics, just remember that some people spend millions of dollars on ways to try to deliberately simulate bad acoustics. hope that helps