Jazz musicians frequently improvise with groupings comprising 4 — 8th notes instead of complete scales.
In a tonal context, these 4-note groups maybe used to delineate a chord change.
1-2-3-5 groupting to outline major anddom chords
1-2-b3-5 groupings to outline minor chords.
In contemporary improvisation, 4-note groupings are often used to go outside the key center.
This can be accomplished by squencing a 4-note grouping through foreign key centers, before resolving back to the correct key. This technique is often appiled to modal tunes, where the imporivser has time to establish the sound of the correct chord, leave the key center, and come back to the original chord.
Return to key center with ii7 V7 I
Playing outside in a tonal context:
There are many possible combinations of 4-note groupings.
The most common ones are derived from the major pentatonis scale.
- The first 4 notes in the scale yield a 1-2-3-5 groupings C D E G
- 1-2-4-5 grouping D E G A
- 1 b3 4 b6 grouping E G A C
- 1 -2-4-5 grouping G A C D
- 1 b3 4 5 grouping A C D E
The 1 b3 4 b6 not used cuz it lacks a perfect 5th and it tends to be unstable and vague.