Harmonische Theorie von Arcas Musik (experimentelle Elektronik mit Pop, einige klassische Einflüsse)

Here's an example (his song Now You Know [2015]). There's clearly lots of effects especially reverb, delay-based effects, and compression. Also, it seems that detuning and modulation/automation play a big part, but I'm still uncertain what's going on to create some of the harmonies here. They don't feel like a typical 1-4-5 or something else poppy. I've done some research and I know he builds a lot of chords by stacking fifths, that's helped me get closer to his sound. Any other ideas?