I’m in love with this Sequential Circuits Prophet sound and wonder how I can find/make something similar to use with the OP-1? (Skip to the 40:40 mark if the video doesn’t automatically start there).
I think at 40:40 it is saxophone. I would use the arp with dr wave with nitro on and a random waveform modulating the filter frequency for the synth at 42:14
That sounds fun.
There are loads of ways! Here’s one…
Use digital synth (press synth then press shift+1 and select digital with the blue knob)
Turn the Blue encoader all the way down
Turn the Green encoader all the way up
White encoder goes just below the mid point
Then turn the red one down too… Alllll the wayyyy 
Set your envelope by pressing 2 on the synth module
Attack (Blue) just a little tiny bit
Decay (Green) just a little to take the edge off
Sustain (White) right down
Release (Orange) doesn’t matter what you do with it just don’t hurt it.
Use arpegio sequencer by pressing shift+the sequencer key under the COM button!
And you should be good to go!
If you’re not getting the sound you want mess with the synth and the envelope!
Hope I helped!!!
May the universe be f*king awesome to you!