·         In Step 17 we looked at the very simplest kind of cluster - two definitive notes in dissonant proximity.  Let's develop these ideas further.

·         A recurring theme in these discussions has been that a chord is a selection of notes from a particular scale, arranged in such a way as to represent the essence of the scale, by reinforcing relationships and implying the missing notes through the overtone series.

·         But there's no reason why notes in a scale shouldn't be combined in ways that don't follow the strict rules of tertian or quartal construction.

·         Take the Eb lydian scale, for example.  Among the chords we can extract from this scale are EbΔ7(9), C-7(9 11), F7(9 11 13), Eb6 9, Aø and so on.  But we could just as well play clusters of notes, or even, if a really dense texture is called for, the whole scale in one Sic Semper Tyrannus of a chord.  Examples [18.1], [18.2], [18.3] and  [18.4] are illustrations.

·         We seem to be coming to the conclusion that it's actually rather arbitrary to elevate tertian or quartal chords to positions of central significance in the harmonic scheme, even though they clearly dominate our experience of mainstream European and Afro-American music.  In reality, there are chords by seconds, chords by fifths, chords by flattened sixths, by fourteenths, by sharpened thirty-thirds, by any interval you care to choose, and by any and every combination of these.

·         So perhaps we should turn our thinking upside-down and, instead of regarding a chord as some kind of offspring of a parent scale, we might picture a scale as a broken chord by seconds!

·         Which brings us to the place where melody and harmony meet.  It is customary to think of them as separate elements.  This is particularly true for the jazz keyboard where the left hand usually bangs out the vertical structures we know as chords while the right hand moves through the horizontal world of melodic line.  But the best players are able to place and voice their changes melodically while shaping melodies with the structural inevitability of a well-orchestrated chord.