This gives a bit more idea that there are samples in Omnisphere (mostly borrowed from earlier Spectrasonic products) that are totally non-electronic in nature. Perhaps not many of you care a whit, but Omnisphere can be used in a zillion different ways to create accompaniments for theremin pieces. I'll do up an example of their guitars which are really nice too. And some really, really nice ethnic instrumental samples. Lots of strings as well (however there are many string libraries out there that are much more realistic - but if you want a smooth string pad, Omnisphere has many great ones as well as some theatrical sounding strings).
Anyway, I was playing around with their Voice Library (which is inherited from their great Symphony of Voices product that used to be the best vocal sample library out there). Lots of choices now. They have a number of Jazz syllable samples that are interesting. Kind of liked the "Dah" sample, so I wrote a little piece trying to use a bunch of different articulations and dynamic ranges to test it out. The samples break down a bit here and there in different voices and the dynamics are not consistent so each voice will need to be manipulated dynamically based on its range (a common issue with samples). Another issue with a sample library that covers the entire choir range is that there will be a cutover between male and female voices - and that cutover might not be where you want it. In that case you need to use individual SATB samples if you can. You can hear some of that in the example I made here as well that uses this one all inclusive "Mixed Jazz Stack Dahs" set.
This is written and played by Notion4, each voice has C2Audio Breeze reverb on it then sound file was exported to Cubase where additional dynamic shaping was added along with EW Spaces Convolution reverb on the mix along with some Wave tape emulation stereo widening. Could do more in terms of dynamic expression.
But in the end, even this is a God-send for composers who want to get an idea of how a piece will sound. I just don't happen to have four really great singers at my disposal right now. I can certainly see writing a much simpler vocal accompaniment to a different theremin melody using this sample (as this is obviously no theremin piece).
Dah Dah! - for acapella quartet