2 Chord Substitution

This chapter attempts to organize information that has to do with replacing chords with others. There are many different ways of thinking about this, and what follows describes just some of them.

Concepts and Terms

  • Soloing and Comping
    • The concepts described here are used both for soloing and comping/harmony.
  • Triads and 7th Chords
    • Most ideas here are illustrated using 7th chords. However, not every substitution has to use all notes from the new chord - the sub can be a triad, or a 2 note chord.
  • Chord Superimposition and Chord Substitution

    • superimposition refers to adding extensions to a chord by superimposing another chord from the same scale over the original. For example, playing Am7 over Dm7 adds extensions 9 and 11 to Dm7 (notes E and G).

    • Substitution refers to replacing the original chord by one from a different scale, frequently with the goal of adding tension that will be resolved. For example, playing AbmMaj7 instead of G7 in the progression G7-C can be thought of as altering the G7 with b9 and #5 (notes Ab and Eb).

  • Functioning and Static Dominant Chords
    • A functioning dominant is a dominant chord that resolves a 4th up (or 5th down), to its I (or i) chord. For example, if G7 is followed by a C chord, the G7 is a functioning dominant.
    • A static dominant is a dominant chord that does not resolve in the same way. For example, if G7 is followed by F7, the G7 is a static dominant.
  • Alterations and Extensions
    • A chord is altered when one or more of its notes is raised or lowered 1/2 step. These new notes are not in the chord’s diatonic scale.
    • A chord is extended when notes are added to it from its diatonic scale.
  • Altered Dominants
    • An altered dominant 7th chord contains the R, 3, and b7 notes, and one or more altered notes (notes that are raised or lowered by 1/2 step): b9, #9, b5, #5.
  • Dominant Resolving to Major or Minor
    • In major V7-I progressions, alterations on the dominant come from outside the parent Major Scale (e.g. using the Altered Scale). In minor V7-i, alterations on the dominant come from its parent Harmonic Minor Scale, and are actually extensions. While it is not illegal to use the Altered Scale to generate alterations in a a minor V-i, it is much more common to use Harmonic Minor. This is because in a minor V7-i in jazz, the V7 harmony usually comes from Harmonic Minor (and not Natural Minor, where the V would not be a dominant chord).

Diatonic Superimpositions

Diatonic superimpositions involve replacing a chord with another chord from the same scale. The replacement chords are built from degrees of the original chord, and are in the same parent scale (e.g. Major Scale). This replacement adds extensions to a chord in order of the scale degrees.

Superimpositions are an alternative way, or maybe a shorthand, of thinking about chords with extensions. Instead of thinking “Dm13” to create a minor 13 sound over Dm7, one might think “Cmaj7” and play Cmaj7 over Dm7, creating the minor 13 sound.

A superimposition built on the 3rd of the original chord is also called “3-to-9”, since the 3rd, 5th, 7th, and 9th of the original chord are now being played.

Note on natural 11th: it seems to be common in jazz to omit the natural 11th in major and dominant chords because it conflicts with the major 3rd. E.g., a D13 would actually be played as D7 with the 9th and 13th.

One application of triads: using a ii minor triad instead of a iim7 chord over the V in a ii-V progression avoids the 11th over the dominant chord. For example, playing Am triad over Am7-D7, results in the notes A, C, E (5, b7, 9) over D7.

  • Example 1: superimpositions over Cmaj7 in C Major
    • Cmaj7 has the notes C, E, G, B. The chord built on the 3rd (E) is Em7 (notes E, G, B, D). Playing Em7 over Cmaj7 adds a 9th to the original Cmaj7, making it into Cmaj9. Playing G7 (G B D F) over Cmaj7 adds the extensions 9 and 11, and playing Bm7b5 (B, C, F, A) adds the extensions 9, 11, and 13.
  • Example 2: superimpositions over Fmaj7 in C Major
    • Fmaj7 has the notes F, A, C, E. The chord built on the 3rd (A) is Am7 (notes A, C, E, G). Playing Am7 over Fmaj7 adds a 9th to the original Fmaj7. However, playing Cmaj7 (C E G B) over Fmaj7 adds the notes G (9th) and B (#11), not 9th and 11. This is because the C Major Scale has a natural B, not a Bb, so using it for building the new chord yields the #11 extension.

In the following two tables, “Orig. Chord” is the original chord, “Sups built on chord tones” contains the diatonic chords built on the 3rd, 5th, and 7th (or flat 7th) degrees of the original chords, and “Extensions” contains all the extensions added (the sup on 7th degree contains all 3 extensions). The other set of columns provides an example in G. Concretely, for the original chord ii (Am7 in G major scale), the diatonic chord built on the 5th degree is the vi chord of the parent scale (Em7 in G major), and playing vi over ii yields extensions 9 and 11.

Table 2.1: Diatonic Substitutions with Major Scale
Sups built on chord tones
Example in G
Orig. Chord 3 5 7 (or b7) Extensions Orig. Chord 3 5 7 (or b7) Extensions
I iii V vii 9, 11, 13 Gmaj7 Bm7 D7 F#m7b5 A, C, E
ii IV vi I 9, 11, 13 Am7 Cmaj7 Em7 Gmaj7 B, D, F#
IV vi I iii 9, #11, 13 Cmaj7 Em7 Gmaj7 Bm7 D, F#, A
V vii ii IV 9, 11, 13 D7 F#m7b5 Am7 Cmaj7 E, G, B
vi I iii V 9, 11, b13 Em7 Gmaj7 Bm7 D7 F#, A, C
Table 2.1: Diatonic Substitutions with Harmonic Minor Scale
Sups built on chord tones
Example in G
Orig. Chord 3 5 7 (or b7) Extensions Orig. Chord 3 5 7 (or b7) Extensions
imMaj7 III#5 V vii°7 9, 11, 13 GmMaj7 Bbmaj7#5 D7 F#dim°7 A, C, Eb
iim7b5 iv VI imMaj7 b9, 11, 13 Am7b5 Cm7 Emaj7 GmMaj7 Bb, D, F#
iv VI imMaj7 III#5 9, #11, 13 Cm7 Ebmaj7 GmMaj7 Bbmaj7#5 D, F#, A
V vii°7 iim7b5 iv b9, 11, b13 D7 F#dim°7 Am7b5 Cm7 Eb, G, Bb
VI imMaj7 III#5 V #9, #11, 13 Ebmaj7 GmMaj7 Bmaj7#5 D7 F#, A, C
  • Examples in Progressions
    • In C major: Dm7 - G7 - C6 -> Am7 - Bm7b5 - Em7
      • Am7 starts on the 5th of Dm7, Bm7b5 starts on the 3rd of G7, Em7 starts on the 3rd of C6.
      • The result is equivalent to Dm11 - G9 - C9.
    • In C minor: Dm7b5 - G7 - Cm6 -> Fm7 - Bdim - Cm6
      • Fm7 starts on the 3rd of Dm7b5, Bdim starts on the 3rd of G7.
      • The result is equivalent to Dm9b5 - G9 - Cm6.

Functioning Dominant Substitutions

In Jazz, functioning dominant 7th chords are frequently played differently than written on a lead sheet, to add tension and interest.

Using alterations (described in the Altered Scale section) is a standard way to add tension, and one way of remembering these alterations is to simply memorize new voicings that contain them. Another way is to use chord substitutions - similarly to supersimpositions, we can use familiar shapes to generate new voicings.

Altered Scale

Chords from the Altered Scale (7th mode of the Melodic Minor Scale) can be used to alter a functioning dominant 7th chord in a major V7-I progression.

The Altered Scale played over its related dominant chord yields the following chord degrees relative to the dominant: R, b9, #9, 3, b5, #5, b7. This scale thus alters the 9th and the 5th of the chord - b9 and #9 instead of 9, and b5 and #5 instead of 5.

The notes of the Altered Scale for a dominant are the same as the notes of the Melodic Minor Scale 1/2 step up from the dominant root (the Altered Scale is equivalent to the 7th mode of Melodic Minor). E.g., the G Altered Scale has the same notes as Ab Melodic Minor.

Chords constructed using the Altered Scale contain the alterations in various combinations.

  • Example: G7alt
    • Playing the Ab Melodic Minor (G Altered Scale) over G7 yields the notes G, Ab, Bb, Cb, Bb, Db, Eb, F. This scale contains G, Cb, and F, which are the Root, 3rd, and b7 of G7. It also contains Ab and Bb (b9 and #9) and Db and Eb (b5 and #5). To use alterations over the harmony for G7, play chords from Ab Melodic Minor over the G7.

The following table summarizes alterations created by substituting a dominant chord with chords from the related Melodic Minor Scale. “MM Chord” is the chord in Melodic Minor, and “MM Intervals” are the MM intervals in that chord. “V7alt Intervals” are the intervals of the same notes in relation to the dominant chord. “V7alt Chord” is the new chord created by playing the MM chord over the dominant. The last 3 columns contain examples over a G7 chord.

Table 2.2: Functioning Dominant Substitutions with Melodic Minor Scale
Example in G
MM Chord MM Intervals V7alt Intervals V7alt Chord MM Chord Notes G7alt Chord
imMaj7 R-b3-5-7 b9-3-#5-R V7b9#5 AbmMaj7 Ab-C-Eb-G G7b9#5
im6 R-b3-5-6 b9-3-#5-b7 V7b9#5 Abm6 Ab-C-Eb-F G7b9#5
iim7 R-b3-5-b7 #9-b5-b7-b9 V7b9#9b5 Bbm7 Bb-Db-F-Ab G7b9#9b5
III#5 R-3-#5-7 3-#5-R-#9 V7#9#5 BMaj7#5 B-D#-G-A# G7#9#5
IV7 R-3-5-b7 b5-b7-b9-3 V7b9b5 Db7 Db-F-Ab-B G7b9b5
V7 R-3-5-b7 #5-R-#9-b5 V7#9b5#5 Eb7 Eb-G-Bb-Db G7#9b5#5
vim7b5 R-b3-b5-b7 b7-b9-3-#5 V7b9#5 Fm7b5 F-Ab-B-Eb G7b9#5
viim7b5 R-b3-b5-b7 R-#9-b5-b7 V7#9b5 Gm7b5 G-Bb-Db-F G7#9b5
  • Examples in Progressions
    • In C major: Dm7 - G7 - C6 -> Dm7 - Abm6 - C6
      • Abm6 contains b9 and #5.
    • In Bb major: F7 - Bbmaj7 -> D7 - Bbmaj7
      • D7 contains #9, b5, and #5.

Tritone

  • Examples in Progressions
    • A7 - Dm7 - G7 - C -> Eb7 - Dm7 - Db7 - C
      • The A7 and G7 are replaced with dominants a tritone away, creating a descending chromatic progression.

Dominants b3 Away

This idea is based on Barry Harris’s approach to using related dominant scales (located in increments of minor 3rd away) over a V chord (referred to as “playing with your sisters and brothers”). Applying this to chords, a functioning dominant can be substituted by any other dominant that is located a multiple of a minor 3rd away.

One of the substituting dominant chords (b5 away) is the tritone sub.

  • Example 1: G7
    • Building a dom7 chord on the bb7 of G7 (3 multiples of b3 up) creates E7, which contains the notes E, Ab, B, D. These are 6, b9, 3, and 5 in reference to G7 - so substituting E7 creates a G7 chord with with 13 and b9 notes.

In the following table, “Sub Chord” is the substitute chord (with the first row simply being the original chord), “Orig. Chord Degrees” are the degrees of the sub in relation to the original chord, and the last two columns show examples over G7.

Table 2.3: Functioning Dominant Substitutions b3 Away
Example in G
Sub Chord Orig. Chord Degrees Sub Chord Notes
dom7 on R R-3-5-b7 G7 G-B-D-F
dom7 on b3 #9-5-b7-b9 Bb7 Bb-D-F-Ab
dom7 on b5 b5-b7-b9-3 Db7 Db-F-Ab-B
dom7 on bb7 6-b9-3-5 E7 E-Ab-B-D
  • Examples in Progressions
    • A7 - Dm7 - G7 - C -> C7 - Dm7 - Bb7 - C
      • A7 is replaced with C7 (built on bb7), and G7 is replaced with Bb7 (built on b3).

Adding movement to a chord

This section describes a different approach to substitutions - instead of replacing a chord with another chord, add other chords to make a new mini-progression, breaking up how long the original chord lasts.

Secondary dominants and ii chords

  • Major, minor, and dominant chords (not m7b5) can be preceded by a secondary dominant - a dominant chord that resolves a 4th up (or 5th down). The secondary dominants (besides the main V) are not in the original scale, but can be played before their resolution chords to add interest. For example, the V chord in C Major is G7 (the dominant of Cmaj7); Dm7’s secondary dominant is A7, Em7’s is B7, and so on.
    • Taking this further, a functioning dominant can be preceeded by its ii chord. This can also be combined with a tritone sub on the dominant - the ii is now relative to the tritone. Generally, the ii chord is minor 7 when resolving to major or maj7, and m7b5 when resolving to a minor, m7 or m6 - but this is not always the case.
  • Examples in Progressions
    • Am7 - Cmaj7 -> E7 - Am7 - Dm7 - G7 - Cmaj7
      • E7 is the secondary dominant of Am7. G7 is the secondary dominant of Cmaj7, and Dm7 is the ii of G7.
    • G7 - C -> Abm7 - Db7 - C
      • Db7 is the tritone sub of G7, and Abm7 is the ii of Db7.
    • Cm -> Dm7b5 - G7 - Cm
      • G7 is the secondary dominant of Cm, and Dm7b5 is the iim7b5 of G7.

Barry Harris diminished approach

  • TODO

Chord shape equivalence

Certain drop2 chord grips on the guitar can be thought of as inversions of other chords. This reduces the number of shapes to learn.

  • m6, m7b5, and 6#11: The drop2 chord built on the m3 of a m7b5 chord is an m6 drop2 chord in root inversion. Because of this, m6 chords can be played with m7b5 shapes, and vice versa. In addition, the drop2 chord built on the b5 of the m7b5 is a maj6#11 drop2 chord in root inversion. For example, Em6 is an inversion of C#m7b5: Em6 contains the notes E G B C#, and C#m7b5 contains C# E G B. G6#11 (shape: x 10 11 9 12 x) is an inversion as well.
  • maj6 and m7: Similarly, The drop2 chord built on the m3 of a m7 chord is a maj6 chord in root inversion. For example, C6 is an inversion of Am7: C6 contains the notes C E G A, and Am6 contains A C E G.
  • dim7: Any diminished shape can be moved by increments of minor 3rds to get its inversions. For example, Ddim7, Fdim7, Abdim7, and Bdim7 are all inversions of each other. This is why there are really only 3 different diminished chords.