Re: Vocal choir kind of synth (as used by Raiders of the Lost ARP)
There aren't that many tho....to get reasonable choir sounds from an analog machine there needs to be quite a sophisticated circuitry, its way more complicated then string sounds which are very easy to make in analog circuitry. For (good) choirs it needs like 3 band pass filters at least and 3 oscies or a divider. The Roland VP330 has some very famous classic ones, and there is the Farfisfa polychrome a rare (supergood) synth from the late 70s which does some cool choir sounds.
A lot of early string keyboards had some "voice" preset but most of the time they were just a string sound with lots of resonance or something and didn't sound like a real choir.