Even the most tin-eared of listeners would hardly confuse a Johann Sebastian Bach piano prelude with a Keith Jarrett jazz improvisation. But despite the 300 years of stylistic evolutions that separate the two masters, they and other great composers share an important musical trait: They move from chord to chord in what feels like a smooth-sounding, economical way.
That economy has manifestations on the printed musical page where, as figure 1 shows, notes of one chord are only slightly displaced to create the following chord. Likewise, Jarrett’s fingers need not move much as he shifts from one chord to the next.
The printed page, however, obscures an important musical quality that is apparent when good music is heard. Music generally is perceived not merely as a series of chords sounded in succession, but also as a series of melodic lines, “voices,” unfolding in time and combining to form harmonies. So,...
