3.2 David Liebman (2013). A Chromatic Approach to Jazz Harmony and Melody. Rottenburg: Advance Music.
Liebman’s publication can serve as a theoretical framework and a treatise on how to step forward from conventional linear jazz improvisation by applying the concepts of tonal and non-tonal superimposition. The author defines his chromatic approach as “the construction of melodies and harmonies which can coexist with, or replace given key centers. It implies setting up contrary tonalities, thus creating a heightened degree of tension and release in order to expand one’s expressive palette” (Liebman 2013:9). The term chromaticism is meant “specifically for a situation in which there is an intentional relationship between melody and harmony. [Because] for jazz, it is the harmonic accompaniment which frames the melody” (Liebman 2013:13).
Liebman discerns three categories of melodies in relation to the diatonic system, to define his concepts of tonal and non-tonal superimposition. In the first category are melodies that stay for the most part within the given harmonic background. If any chromatic tones appear, they are quickly resolved. In the second category are melodies that hold chromatic tones for longer periods. This can be called tonal chromatism. The third category hosts melodies that are not related to any specific overall tonal center, though they may temporarily resolve. This is called non-tonal chromatism.
Tonal chromaticism is achieved by applying techniques of harmonic superimposition, for example, in Liebman’s terms, “tri-tone”, “alternate ii-V”, “scale quality”, “modal”, and “pedal point” substitutions. Although the resulting melodic lines may sound far outside the basic harmonic structures, Liebman still considers these techniques as extensions of the improviser’s conventional chord-scale skills, and uses the familiar chord terminology to identify the notes.
Non-tonal chromatism refers to melodic lines and harmonies in which, in Liebman’s words, no key centers are given priority, but “shape, ambiguous tonality and overall color (resulting from factors of phrasing) are the important aspects” (Liebman 2013: 55). However, although these melodic lines are structured by interval connections, it is still possible to identify their pull towards to temporary tonal centers. Liebman defines these as tonal anchors, which means that in these sort of melodic lines “tonality is flexible and in continuous flux as a line evolves. Within the progress of the line itself, temporary points of tonality may be established as anchors. This is a form of linear tonality and may result from several musical developments: the emphasis of one pitch or pitch cluster, leading tone activity (half or whole tone step pull), rhythmical stress on a pitch, or how the intervallic shape seems to lead to a tonal center” (Liebman 2013: 55).
Liebman argues that in jazz harmony, non-tonal improvisation is a very relative term because any configuration of notes can be identified by using similar chord terminology, the numbered system figured from the root, as in functional harmony, or by constructing complex chords of stacked triads on the root.
How Liebman’s theoretical concepts are put into practice depends on individual aesthetic choices and on the musical relationships in a group of musicians. One group may choose to facilitate musical communication by using names of chords or scales, to create a familiar point of reference. Another, without the need of such a safety net, will be challenged to communicate more instinctively and create fresh reference points. “Harmonically speaking, the spontaneous reference point may turn out to be diatonic or non-tonal; this has to do with the situation, style and particular musicians involved. Achieving a sense of no pervading harmonic center implies the absence of direct superimposition and means that the music is purely intervallic” (Liebman 2013: 30). In this type of playing the improvisers will have to use intervallic recognition as an important tool to react and play by ear instead of by knowledge of chords and scales. According to Liebman, this spontaneous playing in response to the direct musical context, without thinking of tonal references and harmonic relationships, can be truly called free music.