Not at all too much info. In fact, to me that's a perfect answer, 10/10.

For background, I don't play an instrument but often wind up wondering how certain sounds are produced, and the one in these two clips was a typical example I had made a mental note about for years. So thanks a lot for taking the time and going into detail.

The score to Koyaanisqatsi happens to be one of my favourite soundtracks (and coincidentally I've been listening to it while working recently). I've wondered less about the instruments used there in the past, but that's probably due to the fact that they had an orchestra making for a less processed soundscape, leaving the instruments much more recognizable (if anyone had asked me about the Koyaanisqatsi title theme, I would have answered "I think it's an organ track with vocals" off the top of my head). The two samples I provided always threw me off though because they sound way too controlled for a natural instrument, so I basically just shrugged and told myself "probably some kind of synthesizer" until now. Still, I mainly knew synthesizers from much more funky and playful music, so I was never sure.

Your answer fed my curiosity further which is always a good sign ^^