When I was in high school, I read somewhere that all the aspects of creating music could be learned intuitively except for harmony, which we must be taught. I began my study of Bach chorales at the tender age of 12. Mrs. Whitman, my piano teacher, was very strict. The harmonic possibilities of every possible melodic phrase were prescribed. I fought valiantly to use my intuition to create alternate solutions, but ultimately learned the tradition. The reverse has been my process over the subsequent six decades.
Very early in his career, Duke Ellington studied with Will Marion Cook, who advised his young student to solve musical solutions the way everyone else does, and then to find his own solution. Even before I learned this about my hero, I arrived at the same procedure. I have not sought originality to create my own style or to impress anyone, but merely for my music to feel satisfying to me. This was later confirmed when I studied with Al Murray. Al explained the historical progression of style as each successive generation's need to push boundaries a little bit further than the last in order to feel satisfied.
When I was a sophomore in college, I was given an assignment to write an invention in the style of Bach. I lit into it with the gusto I normally reserved for jazz. In a matter of a couple of hours, I was done, and felt really good about it. I was able to be creative within the boundaries of this centuries-old form. My classmates were amazed at what I'd created and my teacher gave me an A. A few days later, I played the invention for my piano teacher, who applauded my achievement, but then added, "But you know this is more chromatic than Bach would have written." Wow! I hadn't even thought of that. In order to satisfy my bebop sensibilities, I went beyond the boundaries of even the most harmonically adventurous Baroque composer. I'm not saying that my little invention is as good as any of Bach's; not at all. He was able to accomplish more with less.
I've felt the same about my jazz compositions and arrangements. I'm always amazed at how writers like Eddie Durham and Neal Hefti could write so simply and not be obvious or corny. I've tried over the years to simplify my music—fewer notes, simpler harmonies, slower harmonic rhythm, more repetition, etc., in order to be more direct so that the players will perform my music better, and the audience will better understand it.
Jazz musicians are obsessed with harmony. They study it and think about it all the time. The irony is that audiences rarely are aware of what is going on harmonically. It's below the surface. It starts with the bass player. He or she sticks out physically playing this large instrument that pretty much goes unnoticed aurally. The musicians on the stand depend on the bass for both the beat and for the roots of the chords. Although the drummer may be the most important member of the band, he or she must be in sync with the bassist to create any feeling of swing or any other groove.
Harmony is the happy coincidence of the vertical confluence of all the melodic lines at any given moment. It doesn't really exist. We freeze a moment and put a chord name on it for our convenience of explaining what we are doing. Think about all the horns in a big band: 5 saxes, 4 trumpets, 3 trombones. Each one of those instruments plays melodies that hopefully sound pleasing together. It's the arranger's job to keep all those musicians happy by giving them fun melodies to play, that interact in interesting ways with all the other horns and with the rhythm section. This can be as simple as 4-part tutti writing or as complex as 12-part dissonant dense structures. It can involve various degrees of counterpoint where different rhythms and melodic shapes challenge each other.
At the same time as all this horizontal melodic material is going on, the arranger must also organize the horns into the vertical chordal structures we call voicings.
Chord names define which pitches are included, but specific voicings denote the vertical order of the pitches as well as the spacing between those pitches. They can be in close or open harmony or anything in between. How the individual voices interact with each other creates intervals that in most cases are very subtle, but make for interesting games between the arranger and the players.
Many years ago, when we were on the road performing Harlem Nutcracker, Art Baron told me how much he loved playing his 2nd Trombone part on a background under a baritone sax solo. The passage alternated between Cmaj7 and Abmaj7+5/G. Art had a B rubbing against Britt's C, and then Art moved down to A and then Ab, which rubbed against Wayne's G. Both Britt and Wayne held their respective C and G through both chords, while Art moved between them. This pattern repeated twice, creating a bit of fun for the trombones while the audience listened to the saxophone melody above. The effect of the trombones is that they color the music in much the same way that sets, costumes and lighting color the action on the stage. It's subliminal, but far from unimportant.
I love playing little games like that. I like to challenge players with unusual combinations of tension and release. Most harmonies are built by stacking notes on top of each other in 3rds, but why not 4ths, 5ths, 2nds, 6ths, 7ths, or combinations? Every once in a while I wind up with symmetrical structures or mirror inversions. I don't try to do any of these things—they just happen as a result of what I hear—what satisfies me musically. My musical satisfaction is deeply rooted in jazz culture, but not limited to those sounds. When I borrow from the European or Latin American traditions, I am careful to put those sounds into a convincing jazz context. The result may expand the boundaries of jazz. This is not only the jazz tradition, but it is who we are as Americans—we welcome immigrants who expand our national identity—sometimes in subtle, but important, ways.