Pentatonics, Modes and Chords

Diatonic Chords

Diatonic chords are the chords that you can make using only the notes of the diatonic scale. Since the diatonic modes are formed by starting the diatonic scale on a different scale degree, the chords will shift with the scale. Tables 1 and 2 show how the chords change with the modes.

Pentatonic Scales

There are a number of pentatonic scales but for this article only the most common major and minor pentatonic scales will be used. Notice that table 1 shows that the major pentatonic scale omits the 4th and 7th scale degrees which also are the notes that do not appear equally in all three major modes. Table 2 shows that the minor pentatonic scale omits the 2nd and 6th scale degrees which also are the notes that do not appear equally in all three minor modes.

Without the chords, the mode that the pentatonic scale is a subset of is ambiguous since each of the associated modal scales have all of the notes of it's pentatonic scale. By the same token, if you know the pentatonic melody, but do not know the customary chords, how do you choose?

About Tables 1 & 2

Table 1: Modal Major Chords
Major Pentatonic 1   2   3   4     5   6     7  
Variable -   3   5 R   3   -   R & 3
Lydian Maj   Maj   min   dim Maj   min   min
Ionian Maj   min   min Maj   Maj   min   dim
Mixolydian Maj   min   dim Maj   min   min Maj  
G Scale G   A   B   C     C#   D   E   F     F#  

Table 2: Modal Minor Chords
Minor Pentatonic 1     2   b3   4   5   b6     b7  
Variable -   R & 3 -   3   5 R   3  
Dorian min   min Maj   Maj   min   dim Maj  
Aeolian min   dim Maj   min   min Maj   Maj  
Phrygian min Maj   Maj   min   dim Maj   min  
A Scale A   Bb     B   C   D   E   F     F#   G  

Major/Minor Pentatonic
Shows the scale degrees that are used, and omitted, for the listed pentatonic scale.
Variable
Shows the note of the chord triad that is variable between the three listed modes where; "-" is all modes the same, "R" is a root note that can be different for the scale degree (these correspond to the scale degree that is not part of the pentatonic scale, "3" is the note that determines if the triad is major or minor, "5" is the note that determines if the triad is diminished.
Modes
Shows the major/minor/diminished state of the chord triad for the listed mode.
Scale
Shows the notes for the scale that is used for the examples in tables 3 & 4.

Changing the Mode of the Rhythm Chords

Table 3: Major Pentatonic: "Amazing Grace" Chords (Key of G)
Lydian midi G G C#o G G G D D G G C#o G G D D G
Ionian midi G G C G G G D D7 G G C G G D G G
Mixolydian midi G G7 C G G G7 Dm Dm7 G G7 C G G Dm G G7
Modal midi G5 G5 C5 C5 G5 G5 D5 D5 G5 G5 C5 G5 G5 D5 G5 G5
Drone midi G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5 G5

Table 4: Minor Pentatonic: "Cluck Old Hen" Chords (Key of A)
Dorian midi Am/G Am/D Am/G Em/Am Am/G Am/D Am/G Em/Am Am Am/G Am Em/Am Am Am/G Am Em/Am
Aeolian midi Am/G Am/Dm Am/G Em/Am Am/G Am/Dm Am/G Em/Am Am Am/G Am Em/Am Am Am/G Am Em/Am
Phrygian midi Am/Gm Am/Dm Am/Gm Emo/Am Am/Gm Am/Dm Am/Gm Emo/Am Am Am/Gm Am Emo/Am Am Am/Gm Am Emo/Am
Modal midi A5 A5/G5 A5 E5/A5 A5 A5/G5 A5 E5/A5 A5 A5/G5 A5 E5/A5 A5 A5/G5 A5 E5/A5
Drone midi A5 A5 A5 A5 A5 A5 A5 A5 A5 A5 A5 A5 A5 A5 A5 A5

If you think of the notes that are missing from the pentatonic scales as the marker notes for the associated modes then the chords that change with the modes are the marker chords since they supply the modal notes. When you play a pentatonic tune with chords from a mode that is not normally associated with it it will take on the character of the mode. It will probably be unexpected, but if you play it over and over it becomes familiar and will start sounding right. Careful, don't play chords to a different mode that other people are playing because in that case, it will sound wrong since it will create dissonance. Playing by yourself it can be fun to change the mode.

Last update 08-Sep-2009