The patch is simple in terms of learning the instrument, but musically rich. Root drone and key so you can do anything over it. It's what Tangerine Dream did with it in the 1977 soundtrack to the movie Sorcerer. Which I've discovered is terribly named, and doesn't actually feature their music prominently. RIP Roy Scheider and slower tempo'd entertainment, but if you're a synth geek, check out their soundtrack which was fuller and more rich than you'll get from the film.
No patch cables, just a little tuning and taking advantage of the Subharmonicon internals. It sends triggers to both VCOs regardless of the rhythms of the sequencers, so we can get a steady drone note out of VCO 2 without much work. The result is that steady droning root and rhythm, allowing us to bring the bass line that VCO 1 provides in and out via the mixer.
Add some slight phasing and reverb for that classic Tangerine Dream sound and you're in it.