An essential element of most music that qualifies as listenable is a balance between musical unity and musical contrast. This is relevant for both composed music and improvised music.
Without unity, the human brain struggles to make sense of what may seem to be random sounds. This may be part of the reason – if not the only one! – that most people have trouble understanding, let alone enjoying, the “12 tone” serial music originated by Arnold Schoenberg in the early 20th century.
Without elements of contrast, music becomes tedious or even boring, possibly even stultifying!
A balance between unity and contrast is something that all improvisers (and composers) should strive for.
Musical unity is mainly achieved through repetition. Since there are so many elements of music, there are many ways to use repetition to achieve unity. Here are some of them:
- Repeating notes
- Repeating a rhythm or rhythmic motif
- Repeating a melodic motif or larger musical idea (for example, in a sequence)
- Repeating a section of a piece
- Repeating a harmonic progression (easy to employ if you are improvising over a standard 12 bar blues progression)
If musical unity is achieved through repetition, then musical contrast is achieved through change (i.e. non-repetition). Here are some ways to achieve musical contrast:
- Changing the melody, for example, its direction (up or down)
- Changing the melodic rhythm
- Changing the phrase structure, for example, by alternating shorter phrases with longer phrases
- Changing the register (tessitura)
- Changing the key
- Changing the meter
- Changing the tempo
- Changing the accompaniment (LH patterns)
- Changing the dynamics, articulations etc.
A landmark example of composed music that fuses overt harmonic unity with requisite contrast is the Prelude to Wagner’s Das Rheingold, from the beginning of the Ring Cycle. In one of the most remarkable introductions in music, the chord of E-flat major sounds for 136 straight measures! Wagner sustains interest during this remarkable expression of harmonic repetition by varying the instrumentation, chord voicings, textures, and dynamics.
A good example of improvised piano music with many sections of extensive harmonic and rhythmic unity set to contrasting RH improvisations is Keith Jarrett’s Koln Concert, or for that matter, just about any improvised 12-bar blues.
While a good improvisation may sometimes stress unity over contrast or vice versa, the most interesting and musically appealing improvisations will finely balance elements of unity with elements of contrast.