Hexatonic scales are six-note scales built from selected pitches within the chromatic collection. They occupy a middle ground between pentatonic simplicity and diatonic complexity.
In Western music, hexatonic scales appear as derived systems rather than primary tonal frameworks.
Definition of a Hexatonic Scale
A hexatonic scale contains six distinct pitches per octave.
Hexatonic scales are formed by:
adding a pitch to a pentatonic scale
removing a pitch from a diatonic scale
selecting pitches symmetrically within the chromatic scale
The blues scale is one of the most common hexatonic examples.
Common Types of Hexatonic Scales
Common hexatonic constructions include:
blues scale
whole tone scale
augmented scale
hexatonic subsets of diatonic modes
Each type emphasizes different interval relationships and tonal behaviors.
Interval Characteristics
Hexatonic scales often:
reduce functional tension
avoid complete harmonic closure
emphasize symmetry or repetition
They are frequently used for color and contrast rather than tonal definition.
Harmonic and Melodic Use
Hexatonic scales are typically used:
melodically rather than harmonically
over static or ambiguous harmony
to introduce contrast within tonal music
They function best as pitch resources rather than complete systems.
The Blues Scale
The blues scale is a modified pentatonic scale that introduces an additional pitch to increase expressive tension. In Western music theory, it is understood as a hexatonic expansion of the minor pentatonic scale rather than a separate tonal system.
The scale is defined by its flexible pitch usage and expressive intonation rather than strict harmonic function.
Definition of the Blues Scale
The blues scale contains six notes per octave.
It is formed by adding a lowered fifth to the minor pentatonic scale.
Scale degrees used:
1, lowered 3, 4, lowered 5, 5, lowered 7
Example in A:
A, C, D, E flat, E, G, A
The added pitch is commonly referred to as the blue note.
The Blue Note
The blue note is not a fixed pitch in performance.
In theoretical notation, it is represented as a lowered fifth, but in practice it may:
bend between pitches
shift intonation
function melodically rather than harmonically
This flexibility reflects the blues scale’s origins in vocal and instrumental expression rather than strict tuning systems.
Harmonic Relationship
The blues scale does not define chord quality by itself.
It is commonly used over:
dominant harmony
minor harmony
mixed tonal contexts
Its pitches often contradict the underlying harmony, creating controlled tension rather than functional resolution.
