I've been on a bit of a David Sylvian kick lately (also found this very interesting and lengthy interview, in which Sylvian is, unsurprisingly, revealed as intensely thoughtful and self-insightful). Some moments in Sylvian's career find him moving as far away from conventional tonality as anyone still working primarily (though not exclusively) in a song-based musical framework - and so I also find myself wondering again at the way listeners who aren't musically trained experience such harmonies. Though I can't claim to be able to instantly decipher some of the denser chords I might hear, my ears have developed sufficiently that a lot of that comes pretty much without thinking...or when I'm wrong, I'm wrong by being half-right. (Example involving a rather interesting chord, whose source I now can't recall, except that it was on guitar: I thought I was hearing an augmented chord, but what it turned out to be - I was curious enough after hearing the song it's from in the car to listen again once I got home, and figured it out on the guitar - was a sort of stacked chord that might be called a D11+ or something: D-F#-A-C-E-G# (the F# was implicit). What's interesting is that all four basic chord types are present, three notes at a time, within this chord: major (D-F#-A), diminished (F#-A-C), minor (A-C-E), and augmented (C-E-G#). Or: it's an augmented chord with the bass raised a whole step...why I was hearing an augmented in the first place.)
Anyway, the point is that I'm aware that most people who aren't musicians (and many who are) can listen to lots and lots of music, and be pretty expert as fans or even critics, without necessarily looking at it in theoretical terms. My working theory is that complex harmonies "translate" to tone color, that you can play a simple chord on a piano, say, then play the complex chord, and people will hear the sounds as texturally more complex. (Which, in terms of the physics of sound, they actually are.)
These two David Sylvian songs are a good test of that in some ways. First is a song Sylvian himself regards as the pinnacle of his first band Japan's career, "Ghosts," from that band's final album Tin Drum. While there's a fairly simple song underlying what we hear, seemingly every other musical phrase has a new synth sound attached, many of which are artfully detuned or feature altered overtone series - that is to say, they're warped tonally, timbrally, even if the actual notes sounded are relatively straightforward. (And they're not always that.)
The second song I'm posting is Sylvian's 1989 single (a bit of a jab at Virgin Records' demand that he release a single to go with the Weatherbox compilation), rather cheekily titled "Pop Song." Cheekily, because on first listen, it's anything but. As George Harrison said (in a song that followed its own rather winding harmonic pathway), "If you're listening to this song, you may think the chords are going wrong." But also cheekily because, listen to it a few more times, and you realize there is too a pop song buried underneath the crabbed, intertwined harmonies. From those dense harmonics melodic counterpoints can be extracted...and even the song's slightly off-center chord structure reveals itself as a variation on your basic fifties I-vi-VI-V progression (often abbreviated to I-vi). And those squiggly, near-Zappa-like, jagged instrumental interjections? I imagine you could play many of them at half speed, or offset by a sixteenth- or eighth-note, and they might sound almost normal. "Pop Song" is essentially a détourned pop song.
Japan "Ghosts" (Tin Drum, 1981)
David Sylvian "Pop Song" (single, 1989)