Scott Spiegelberg at Musical Perceptions and James Cook at Mathemusicality have started a discussion about tonality and harmony, where, to oversimplify, Scott is in favor of chord progressions and James takes more of a voice-leading approach. The discussion continues here (James) and here (Scott). I've never understood tonality, and reading these posts, I see that even the experts don't understand tonality either, at least not in any kind of consistent way. I'm learning a lot from the discussion, but Heather at In the Wings has a serendipitous perspective on the harmony in Brahms that touches on my ambivalence towards tonality.
In my case, very little of the music I listen to, or perform, is tonal. Electronic music gets its tension and release from changing textures and timbres. Most contemporary classical music isn't really tonal either, but even in the tonal pieces that I play (for example, some of Mompou's Cancion y danzas), I can identify the cadences, but not the chords in the middle.
So why am I interested in harmonic theory? I have a number of books that recommend harmonic analysis as a memory aid (and Heather's post alludes to this aspect). And that's ok, as far as it goes. But in late romantic and newer music, does anybody ever listen for these kinds of harmonic progressions? A former piano teacher claimed that he could hear the key shifts in symphonic music, but such skills are beyond me. When I played pop songs on the guitar, I would try to figure out the chords from recordings, but I'm not learning classical music that way. After all, I have the sheet music in front of me. If I'm playing jazz, then it's important to know the harmonic underpinnings of a song so I have a pitch set, and perhaps some intervals, to use in the improvised line. But eventually even jazz pianists take such liberties with the harmony that we get some pretty strange chords (I have one book that shows a B-flat seventh flat ninth flat fifth, or a G major 13th sharp ninth — I mean, really). It would be different if I played much music from the period where tonality was strongest, such as Mozart and Beethoven, but I've never cared that much for the classical period (this kept me out of music school in my younger days). The memory aids that I need for Ravel, Cage and Takemitsu really have nothing to do with their harmonies, and more with what James Tenney, in his wonderful book Meta + Hodos, calls "clangs," sound gestures with several defining parameters. I'm still interested in learning more about harmony, yet another of my extended projects….