CHORD SUBSTITUTIONS

 

Contents

Chord Substitutions


       Why Chord Substitutions?
       Diatonic Substitutions
       Chord Degrees
       Chords that Share most Similar Notes
       Relative majors and minors
       Second, Dominant Chords Alternative: Diminished
       Examining Chord Progressions to Find Substitute Chords
              Interpolation and Back Cycling
              Using the Dominant and Secondary Dominant
              Bass Note Reharmonisation
              Substitution for Effect
              Relative Majors and Minors
              Majors and Minors
              Scale and Degree Notation
              Chord Family Substitutions

                      Inversions
                      Flat-Five Substitution (Tri-tone)
                      The iii for the I
                      Minors into Majors
                      Majors into Minors

 

CHORD SUBSTITUTIONS

Chord substitutions means exactly what they say, i.e. replacing one chord with another.
However, you need to know which chord replacement works and which doesn't in view of theory, practice and good hearing ability.

 

Chord substitutions are used to create a different harmonic sound in the music.


This lesson will teach you how to find the right chord substitutions that will make sense musically.


Every key has primary chords built off the 1st, 4th, and 5th tones of the scale.

 

In the key of C, it's C-F-G, in the key of G, it's G-C-D, in the key of D, it's D-G-A, so on…
The 2nd, 3rd, 6th, and 7th intervals create the secondary chords.


In C major:


C is 1
Dm is 2
Em is 3
F is 4
G is 5
Am is 6
Bo7 is 7

 

C
Dm
Em
F
G
Am
B07
                   

 

 

Why Chord Substitutions?

While Chord substitutions are more for intermediate to more advanced students for the most part but basic-lesson students can also gain some insight into how chords work throughout our music and start understanding what they and we hear in our music all of the time.


You will really enjoy the extra colour and depth that interchanging chords can bring into your own music if you are a composer or an improvised performer. The possibilities are endless when it comes to what we can do with music through chords.


Assuming that you’re working on a song idea and playing some chords and you start on G, switch between C and G a few times, then to D, and resolve in G.


That chord progression sounds quite good but seems a little too familiar, when your goal is to create something new and unique. So how do you shake things up to find a catchy and impressive chord progression to complete your song that truly sounds like your own?


One great way is to use chord substitutions. Swapping out a chord or 2 can really liven up a progression and also help you discover new melodic ideas to sing.

 

Particularly, when you’re working within the family of diatonic chords, which have many notes in common, you can make substitutions that subtly change the sound and mood of a progression while leaving intact its basic movement.


Moreover, even if you’re not a song writer, you can still use substituted chords to add colour and interest to the song that will impress your peers.


Here are some simple substitutions you can try in your song writing.


Diatonic Substitutions

Diatonic scale is a seven-note musical scale with 5 whole steps (i.e. C, D, E, G, A, B) and 2 half steps (i.e. E to F and B to C), whereas Chromatic is the musical scale with 12 pitches that are a half step apart (i.e. C, C#, D, D#, E, F, F#, G, G#, A, A#, B).

 

Harmonizing the diatonic scale produces chords with different sounds. These chords have different qualities which produce different effects when played in a piece of music. Though these chords offer a wide range of expression, musicians often want to add variety and surprise to their music.

 

A Diatonic substitution is when you substitute (sub) one chord in a Diatonic Key with another chord in the same Diatonic Key.

 

This is accomplished by substituting existing chords with ones that sound different but accomplish the same harmonic function. When the new chord belongs to the same key as the original chord, it is called a diatonic substitution.

 

Eg. For the I chord you can use the iiim or the vim. In the key of C that would mean using a Em or an Am respectively, as a sub for C. Listen carefully and detect their sound similarity.

 

C
Em
Am


In the key of G, the iiim or vim would be Bm or Em, respectively.

 

G
Bm
Em

 

It is easy to find chords with common notes in the context of a key signature. Try, if you can, to examine the 7 chords in a given Key. You will find that every chord has an alternative. The way to find these is simple: each diatonic substitution is separated by a diatonic 3rd above or below the root.

 

Let's examine this.


Does it appear to you as if every chord could be sub for any chord? No!


Where would you draw the line and how would you figure out which are the best sub chords?


Answer: Explore how many shared notes the intended sub chord has with the original chord.

 

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Eg. In C Key: Why Am7 or Em7 are good possible subs for Cmaj7?


Note that Cmaj7 (C E G B) shares 3 notes out of 4 (that’s 75%) with Am7 (A C E G) where ‘A’ is a 3rd below C and Cmaj7 (C E G B) shares 3 notes with Em7 (E G B D) where E is a 3rd above C.

 

Moreover, when the sub chord (say Am7) is played with the bassist still playing the root C in a band, it will sound like C major 6th – i.e. The bassist letting the listener know that it’s a C chord while the ‘A’ root note from Am7 is like the 6th of C key.

 

Likewise, if you play Em7 while the bassist is playing C root, it sounds like C major 9th. Why is this so? The E root from Em is the 2nd and 9th of C key, and since there’s a 7th there from Em7 it sounds like C maj9 (and not C2).

 

To illustrate further:

 

C2 usually means a Csus2, which is C,D,G with no 3rd.
C(add 2) would be C,D,E,G.
C9 includes the b7 to make it a dominant: C,E,G,Bb,D.
C(add 9) would be C, E, G, D, with the D being in an octave higher.
C7 chord always has a b7, and anything above that 7 chord implies that the 7 is a b7.


Therefore, C7, C9, C11 and C13 all have that b7 (Bb) in there.

 

The b7 is implied always for C7, C9, C11 and C13.

 

The following diagram shows us that an Em triad is the same as Cmaj7 without the root.

CmajEm

Cmaj7
Cmaj7 without C root
Em

 

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Chord Degrees

Just as scale degrees are designated by Arabic numerals (1, 2, 3...7), chords are similarly designated by Roman numerals (I, II, III ... VII).

 

For example, in the key of C major the notes are C,D,E,F,G,A,B and they are designated as 1,2,3,4,5,6,7. However, when we consider them in chord names, for instance, the triad chords in the key of C we have Cmaj, Dm, Em, Fmaj, Gmaj, Am, Bdim. These are designated I,II,III,IV,V,VI,VII.

 

When speaking about these chords, in the key of C major, we would call Gmaj the dominant 5 chord, Fmaj the sub-dominant 4, Dm the 2 chord and so on. If it’s in the key of G, then dominant 5 would be Dmaj, Cmaj would be the sub-dominant 4, Am would be the 2 chord and so on.

 

While there is no single agreed-upon system for numbering chords, one common system uses upper-case and lower-case Roman numerals to distinguish whether a chord is a major or a minor (Dm=ii, Fmaj=IV, Am=vi and so on).

 

The Harmonizer uses upper-case Roman numerals for all chords. However, if the chord happens to be minor, a lower-case "m" will appear next to the Roman numeral (eg. VIm). In the case of diminished chords such as the seven chord, the Roman numeral will be followed by a superscript circle (Bo).

 

Scale

 

Assuming that you’re working on a song idea using the I IV V chords. That chord progression sounds perfectly good but seems a little too familiar, when your goal is to create something unique. I'll teach you how to find a chord progression that feels and sounds really like your own?

 

One great way is to use chord substitutions. Swapping out a chord or two can really liven up a progression and also help you discover new melodic ideas.

 

We usually look for chords that share the most similar notes, as chords in a Diatonic key. You’re working within the family of diatonic chords, which have many notes in common, you can make substitutions that subtly change the sound and mood of a progression while leaving intact its basic movement.

 

Here are some simple substitutions you can try in your song writing.

 

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Chords that Share Most Similar Notes

 

Primary-Secondary Chord Substitutions


Each relative minor key of a Major key that shares the most similar notes is as shown below:

 

MajorRelativeMinor

 

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Relative Majors and Minors

The easiest kind of substitution is to swap a major chord with its relative minor or vice versa. These pairs of chords are closely related, having 2 of their 3 notes in common.

 

For instance, a C major chord is made up of the notes C, E, and G, while its relative minor, Am, has the notes C, E, and A. So you can substitute an Am chord for a C major chord, or vice versa, for a smooth but noticeable change in the sound of the progression.

 

You can sing the same melody over either chord.
Every major chord has a relative minor (and every minor chord also has a relative major), and you can substitute one for the other no matter what key you’re in.

 

These relative major/minor pairs allow you to have a whole lot of possible substitutions in your song-writing arsenal.

 

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So, if the bassist is playing C root, while you are playing Em, it will sound like Cmaj7. On the other hand, if the bassist is playing an E note while you are playing the Cmaj7 chord, it will sound like the first inversion of Cmaj7.

 

Notes Position for Cmaj7: C-E-G-B where C is the root (the lowest note).
Notes Position for First Inversion of Cmaj7: E-G-B-C where E becomes the lowest note.


The diagram below shows that when you add a b7 to Em it becomes Em7 chord and it is like Cmaj9 without the C root.


Cmaj9E7

Cmaj9 with C root
Cmaj9 without C root
Em7

 

 

So, if the bassist is playing C root, while you are playing Em7, it will sound like Cmaj9.
On the other hand, if the bassist is playing an E note while you are playing the Cmaj9 chord, it will sound like the first inversion of Cmaj9.


Notes Position for Cmaj9: C E G B D
Notes Position for First Inversion of Cmaj9: E G B D C


Other chords within the key or without the key may also offer interesting options for jazz guitar chord substitutions.


Feel free to analyse, research & explore to make sure that it sounds good to you! It is not as simple as merely knowing the musical theory. You have to listen and figure out which voicing fits the best and which you might want to avoid in certain situations.

 

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Second, Dominant Chords Alternative: Diminished

While still exploring common tone substitutions, let's get into a specific chord type: the dreaded dominant 7b9 chord! The spelling for this chord is fairly simple; 1 3 5 b7 and b9. It can be used as a resolution in most V-I situations such as G7b9 to C.


The beauty of the dom7b9, as we'll see in a second, is in its symmetrical nature when we omit the root. We're left with a Bdim7 when we leave out the root in a G7b9 chord.

 

The dominant will get the symmetrical characteristics of its related diminished.


Since the diminished chord is symmetrical in nature, it is movable up and down in minor 3rds. In other words, Bdim7 is, in fact, the same chord as Ddim7, Fdim7, and Abdim7. They all contain the same notes.

 

Note: Don't forget their enharmonic equivalent: Ab = G#, and so on.

 

G7flat9BoDoFoAbo

G7(b9)
B07
D07
F07
Ab07
         

 

Try it for yourself. Do you hear how each of these is a possibility over G7b9?


Or, more simply, play a diminished 7th chord from the 3rd, 5th, b7th or b9th of any dom7(b9) chord.


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Examining Chord Progressions to Find Substitute Chords

By examining a specific progression it is possible to find substitute chords. The most common way to look at this is to find progressions that share the same destination.


Interpolation and Back Cycling

Jazz musicians play the ii-V cadence most of the time when resolving to the I chord. Therefore, the V-I can become ii-V-I. This concept is called interpolation.


Let’s try adding the V's related iim7 chord before it.


Using the Dominant and Secondary Dominant

A Secondary Dominant is the Dominant of a Dominant (See more on Secondary Dominant)


G7Cmaj7Dm7G7Cmaj7

G7-G7-Cmaj7
Dm7-G7-Cmaj7
   

 


G7 is the Dominant of Cmaj7. Adding a G7 before Cmaj7 is adding a Dominant of Cmaj7, and adding a Dm7 before G7 is adding a Secondary Dominant of G7.


This principle works fine even if there's no resolution to the I chord. Simply add the appropriate ii chord or II chord in front of the V (D is the Dominant of G). The example below is adding a II instead of a ii.



7G7C7F7toAm7D7Dm7G7Gm7C7Cm7F7

D7-D7-G7-G7-C7-C7-F7-F7
Am7-D7-Dm7-G7-Gm7-C7-Cm7-F7
   

 

 

 

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Next, let's look at how we resolve to the I chord.


Earlier, we have V-I becoming ii-V-I. Next, we can add iii-VI before ii-V-I.


Further, we can apply the Secondary Dominant technique again to improve the chord progression, by adding firstly a VII before iiim. (B7 is the Secondary Dominant of Em) and then add another Secondary Dominant vii#m before VII (F#m is the Secondary Dominant of B7).


Em7A7Dm7G7Cmaj7F#m7Em7A7Dm7Cmaj7

Em7A7-Dm7G7-Cmaj7
F#m7B7-Em7A7-Dm7G7-Cmaj7
   

 

 

 

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This concept is called back cycling. Each added chord is the dominant of the next chord. In other words, Em7 is the V of A7, A7 is the V of Dm7, Dm7 is the V of G7, and G7 is the V of Cmaj7.


Back cycling is to create Tension and interest in your lines and comping that you eventually resolve after the Tension has built to a climax.


Of course, there are numerous more other possibilities. They are yours to discover. Listen to pianists and guitarists on jazz recordings and find your own favourite back cycling tricks.

 

Bass Note Reharmonisation

Another great technique is to simply use the bass note as the focal point for your reharmonisations.

 

It’s really a wonder how moving around just one note can yield a bunch of different sounds. This will usually be up to the bass player, but can take advantage of some of this stuff as well, even if you're playing in a solo or duo setting.

 

This is How it Works.
If you play an Em7 chord, adding a C in the bass would create a Cmaj9.
C E G B D

 

Em7
Em7 with C bass root > Cmaj9


Let's try on a C major triad by adding A to the bass. This gives us Am7.
A C E G

 

C
C with A bass root > Am7


So far, these have all been mostly based on diatonic substitutions. Let's try something else.


If you play a G major chord and you put an A in the bass, it will give you a close to Gsus2 sound, although Gsus2 is not supposed to have a B note. It’s supposed to have only G A D notes.
A G B D

 

G
G with A bass root > Gsus2
Actual Gsus2
     

 

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Substitution for Effect

Another reason for substituting chords is to add interest to a piece of music.

 

If you have a rather long bland chord progression, you can add chord extensions and extra chords to spice it up. For example, the original progression below has a long dull stretch of Cmaj.

 

cccccccccc6cmaj7c6cc6c#m7b5a7..

C-C-C-C-C-C-C-C
C-C6-Cmaj7-C6-C-C6-C#m7b5-A7-Dm7-Dm6-G7sus-G7-C-C6-Cmaj7-C6
   

 


We can have an enhanced Progression by adding harmonic extensions to the existing chords and inserting extra chords to break the monotony, as shown above.

 

Most of these extra chords (such as C6 and Cmaj7) are simply based on the original chord C.

 

However, a very effective double change (C#m7b5-A7-Dm) now leads into the Dm section.


The A7 to Dm creates a V7-iim harmonic movement. The C#m7b5 acts as a bridge to get us to the A7 from the C-based chords.


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Relative Majors and Minors

The easiest kind of substitution is to swap a major chord with its relative minor, or a minor chord with its relative major.


These pairs of chords are related in the sense that they have 2 of their 3 notes in common.


For instance, a G major chord is made up of the notes G, B, and D, while its relative minor, Em, has the notes E, G, and B. So you can substitute an Em chord for a G major chord, or vice versa, for a smooth but noticeable change in the sound of the progression - and usually you can sing the same melody over either chord.

 

G
Em

 

Note: Never change the main melody line to accommodate to your substituted chord (s), but, instead, ensure that your substituted chords can support and harmonise with the main melody.


Majors and Minors

In the Common Chord Substitution section of the Harmonizer the one chord (I) of the major scale is found at the top of the column of chord roots. This chord is derived from the major key as appearing in the key designator of the Major and Natural Minor Scales section.

 

A chord's theoretical name indicates its relationship to the other chords of the key and gives musicians a way to talk about chords without being specific to a key.

 

For the purpose of substitution, it is important to understand what position a chord plays so that the proper substitution can be made. Musicians also refer to chord positions by their Roman numeral equivalents. The tonic is the one chord. The subdominant is the four chord. The dominant is the five chord.

 

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Scale and Degree Notation

Substitutions do not work in every case. There are some specific and even complicated rules for substitution, but the final arbiter of a successful chord substitution is how it sounds. We will look at three basic rules for substitution: chord family, inversion, and flat five.

 

Chord Family Substitutions

It is helpful to know the functions of the chords in order to make successful chord substitutions. The diatonic structure consists of three families of chords: tonic, subdominant, and dominant.

 

The tonic family expresses the tonal foundation of a key. The subdominant family expresses movement away from the foundation. And finally, the dominant family expresses harmonic tension. This tension is released with chords that move the harmony back to the tonic. Chords belonging to the same family can often be substituted for each other.

 

More on Tension Here

Chord Families

 

 

The diagram below shows the similarity between notes when chord families in the key of C major are grouped together.

 

Chord Families Note Similarities

 

 

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Inversions

Another kind of chord substitution is accomplished by rearranging the notes of a chord to produce a new chord. Below is an example of some of the chords in the key of C major that are inversions of each other and can usually be used interchangeably.


C Major Inversions

 

C6
Am7
Dm6
Bm7b5
       

 

Because of its construction, a diminished seventh chord (dim7) offers several inverted combinations that work as chord substitutes. This chord is made up of four notes spaced a b3rd (minor third) apart. The notes of the diminished seventh repeat every 1-1/2 steps up or down the scale.

 

The diminished seventh chord is not diatonic to the major scale; instead it is derived from the harmonic minor scale.

 

Minor 3rds

 

B07
D07
F07
Ab07
       

 

 

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Flat-Five Substitution (Tri-tone)

Another kind of chord substitution which is often used in pop and jazz music is known as flat-five substitution. This substitution is made by replacing a dominant chord with a new dominant chord whose root is a diminished fifth interval above the original chord’s root.

 

For example, in the key of C major, a G7 could be replaced with a Db7. (G to Db is a diminished fifth interval.)

 

C-Am7-Dm7-G7
C-Am7-Dm7-Db7

 

This is not a diatonic substitution because Db does not belong to C major. However, the two chords do share a tritone interval.

 

A tritone interval is actually a diminished fifth (or augmented fourth) interval. This interval is made up of 3 whole steps, thus the name tritone.

 

This substitution works because these two chords resolve to the tonic chord in similar ways. In the key of C the dominant chord is G7. The flatted fifth of G7 is Db7, which becomes the substitute chord.

 

The example below shows that the second and fourth notes of these two dominant chords resolve to the first and second notes of the tonic chord by descending or ascending one half-step.

 

Tritone Intervals

 

 

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Another reason this substitution works, even though it is not diatonic, is that the root of the substitute chord which creates harmonic tension descends a half-step to the root of the tonic, creating a descending chromatic bass line.

 

The tritone interval of the original dominant chord and its flatted-fifth substitute allow the tension created by these chords to be released by the tonic chord.

 

Another interesting characteristic about the tritone interval is that 2 tritone intervals added together produce an octave.

 

As in the example shown above, when we go up the scale 3 whole steps from F (the 2 note of Db7), we land on B (the 4 note of Db7). When we go down 3 steps from F, we land also on B but an octave lower than the 4th note of the chord. You can see that Db7 and G7 share the same tritone interval from F to B and from B to F.

 

Nevertheless, Tritone substitute does NOT work for every chord progression. Listen and trust your ears.

 

Lessons Recap
To recap our earlier lesson, every major chord has a relative minor and every minor chord has a relative major. You can substitute one for the other irrespective of the key.

 

MajorRelativeMinor

 

If you understand chord formation and how chords are built you need not learn these pairs by heart. Otherwise try memorising these relative major/minor pairs, and you’ll have a whole bunch of possible substitutions in your song writing and improvisation arsenal.


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The iii for the I

Within the diatonic chord family, another good substitution to try is the iii for the I (see Diatonic Sub-chord column above ). In the key of G, that means substituting a Bm for a G. The iii makes a nice transition chord between the I and IV and between the I and V.


Minors into majors

You can also substitute chords outside the diatonic family, sometimes called non-diatonic chords. These chords stand out more in a progression than diatonic chords do, because they include notes not in the scale of the song’s key, and can be used to great effect.


Below are a few examples that involve substituting major chords for the ii, iii, and vi which the diatonic minor chords in a major key.


Compare these 2 progressions. The 1st has a minor ii (Am), and the 2nd has a major II (A). Notice the contrast in sound even though only one note

changes. The Am has a C note while the A major has a C# note.


I ii V
G Am D

I II V
G A D

 

Coming from the I, the ii (often played as a ii7) pulls strongly toward the V, thus it’s most often followed by a V. You can hear this ii–V–I sequence in lots of country and bluegrass tunes.

 

I II V7 I V7


Using the major III (or III7) instead of the diatonic minor iii has a similar effect as substituting the major II for the minor ii.


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Majors into Minors

In addition to turning diatonic minor chords into majors, you can do the opposite, by turning diatonic majors into minors - such as replacing a diatonic major IV with a minor iv, or a diatonic major V with a minor v.


The Beatles made brilliant use of these chords to differentiate sections of songs. The verse and chorus of “I Want to Hold Your Hand” have the V, but then the bridge (“And when I touch you . . .”) kicks off with an arresting minor v.


Similarly, “She Came in Through the Bathroom Window” uses I-IV in the verse and then I-iv in the bridge (“Didn’t anybody tell her?”).


“I Want to Hold Your Hand,” the Beatles:


chorus IV V I vi IV V I
bridge v I IV ii v I
IV V IV V IV V


“She Came in Through the Bathroom Window,” the Beatles:


verse I IV
bridge I iv 2x
bVII bIII bVII bIII


Radiohead’s “Creep” uses the major III as well as both the major IV and minor iv, to powerful effect.


“Creep,” Radiohead:

I III IV iv


As you experiment with substitutions in your song writing, let your ears guide you. If you find a substitution that sounds good, pay attention to where the progression wants to go next. Good chord progressions have a momentum and direction of their own, and often the best songs come when you follow their lead.

Dr Pierre CHENXU

 

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