Not sure what you mean exactly by harmonies. Especially 12 of them. One or two, ok, a third and a fifth up to create triads, but 12 ? Or do you mean doubles or triples, which is the same line sung two or three times ? Or do you mean vocal stacks, which is 30 times the same line (yes, Devin, I meant you when I said that) ?
Also, I don't know what to think of a singer who refuses to sing harmonies (of any kind). Like, WTF ?
In any case, sampled choir in the center of attention ? Pretty difficult and the few things that are out there aren't exactly cheap or versatile.
The other vocal parts for this song are pretty extensive, and she's done... Not the best answer, but OK. I could leave this out and do something else in the space - strings or something - but I'd like to try this in part because it's not something I've done before.
There are doubles and harmonies in these 12 parts, so it's would probably require her to sing this same line more than 30 times to get the takes that we need. There are no words in this part, only an "ah" sound. I'm actually happy with the humanized MIDI, other than the quality of the actual "Ah" sound, so I think I'm close.
We do two music video productions a week and I understand that she's ready to move to the next song already, so I'm OK with her desire to not do this part, but I'd like to try to achieve the first goal before abandoning it to an alternative instrument sound.