A Guitarist’s Guide to Chord Substitutions, Part 1: Diatonics

A great song doesn’t need to be complex rhythmically, harmonically, musically or lyrically; it just needs to be relatable to the masses and touch a nerve in the listener.

I’m pretty sure most of us have listened to a hit and said “I could’ve written that.” The fact of the matter is that most Top 40 songs are not especially intricate, but what they all have in common is that certain something that connects with an audience.

I lived in Nashville for 17 years and co-wrote with some of the worlds’ best songwriters. Those amazing people knew their craft inside and out, and trust me, songwriting is a craft that can be learned by almost anyone. Writing a great song, however, is a whole other matter.

Of course there are a million ways to get started. Some people begin with a groove, others a chord progression, many with a melodic hook, and more often than not (at least in Music City), a song title.

Whether you’re new to songwriting and instrumental composition or are simply trying to develop your playing chops, there are harmonic tools and techniques that will help you make more of your chord progressions and add emotional interest. In this posting, we’ll focus on one of the simplest of these tools: diatonic chord substitutions.

Diatonic Chord Substitution

Let’s start by breaking that sentence down. “Diatonic” simply means from the same scale. “Substitution” means you are going to swap certain chords for other chords based on their harmonic composition (i.e., the notes they are made up of).

In this posting, we are going to learn which chords can be swapped for other chords within the same scale. The reason chords can be substituted is that they contain some of the same notes. Within three-note chords (triads), two of the notes will be the same; within four-note chords (seventh chords), three of the notes will be the same. (For more information on triads and seventh chords, read this blog posting.)

Three-Note Chords (Triads)

Here are the seven triads (three-note chords) built from the C major scale (C – D – E – F – G – A – B – C):

I       II       III    IV   V      VI      VII

C – Dmi – Emi – F – G – Ami – Bdim

The general formulas for diatonic three-note chord substitution are as follows:

1. The root chord (the I) can be interchanged with the III and VI chords.

In the key of C, that means you can play Emi or Ami instead of the C major chord (CEG). As you can see, both Emi (EGB) and Ami (ACE) contain two of the notes also found in the C major chord: E and G in the case of Emi, and C and E in the case of Ami. So just remember I – III – VI.

2. The IV chord can be interchanged with the II chord.

In the key of C, that means you can play Dmi (DFA) instead of F (FAC). As you can see, Dmi contains two of the notes found in the Fma chord (F and A). All you have to remember is II – IV.

3. The V chord can be interchanged with the VII chord.

In the key of C, that means you can play Bdim (BDF) instead of G (GBD). Bdim contains two of the notes found in the G chord (B and D). Just remember V – VII.

Four-Note (Seventh) Chords

The same chord substitution formulas work for four-note seventh chords. In this case, the substituted chords will contain three of the same tones.

1. In the key of C, Emi7 and Ami7 can substitute for the Cma7 chord:

I                   III                  VI

Cma7            Emi7             Ami7

C – E – G – B       E – G – B– D      A – C – E – G

2. Dmi7 can substitute for the Fma7 chord:

IV               II

Fma7         Dmi7

F – A – C – E    D – F – A – C

3. … and Bmi7(♭5) can substitute for the G7 chord:

V                 VII

G7             Bmi7(♭5)

G – B – D – F       B – D – F – A

Try It for Yourself

Chord substitutions are a powerful harmonic tool that can expand your songwriting and playing skills — even melodic improvisations.

Let’s put it to the test. Start by playing this chord progression:

IV      I        V       I

II:    Fma7  / C   /  G    / C    :II

Now try swapping Ami (VI) for the first C chord (I):

IV      VI        V        I

II:    F   /  Ami  /   G   /    C    :II

Then try swapping Dmi (II) for the Fma7 (IV), Bmi7(♭5) (VII) for the G (V), and Ami (VI) for the C (I):

II         I            VII        VI

II:    Dmi   /   C  /   Bmi7(♭5)  / Ami    :II

To hear how effective this is, return to the original progression. Note that you could use any or all of these substitutions as separate sections of a song, or as an eight-bar progression.

Melodic Substitutions

If you enjoy playing single-note arpeggios when you improvise, you may want to try using diatonic chord substitution to expand those melodic chops as well. Here’s a simple example to get you thinking about this in more detail:

Over the following Cma7 chord progression, try using an Emi7 or Ami7 arpeggio as your single- note melody:

Cma7 – C – E – G – B

Emi7 arpeggio: Emi7 – E –  G – B – D

(The D note will sound as a second or a ninth against the Cma7 chord.)

Ami7 arpeggio: Ami7 – A – C – E – G

(The A note will sound as a sixth or thirteenth against the Cma7 chord.)

The Video

In this video, I’ve recorded an eight-bar chord progression that utilizes the chord substitution ideas described above, over which I add a nice melodic line and slide parts.

Note how the changes in the harmonic structures (i.e., the chord substitutions) affect the way the melodies I play relate to the progression. In other words, your chord choices will give your melodies more variation and musical mileage.

The Guitars

I’m using Yamaha Pacifica Professional PACP12M and Revstar RSS20 Standard guitars for the above video. Rhythm and lead guitar tones were all recorded using the Line 6 HX Stomp modeling processor.

Pacifica Professional

The Rupert Neve and Yamaha-co-designed Reflectone pickups (shown below) allow complex chordal passages to translate cleanly, even when used with a little overdrive. The tremolo bar is super-smooth for chordal shimmers, and the guitar stays perfectly in tune even on those single-note lines. The satin-finished maple neck is a fast and easy-to-navigate slim C-shape, which pairs musically and resonantly with the acoustic design technology-contoured alder body.

The Pacifica Professional is an extremely versatile guitar that can be used for any style and almost any musical application, making it perfect for the studio as well as live performance.

Revstar RSS20 Standard

The chambered mahogany body and neck-through body construction really add sustain to the entire range of Revstar guitars. The two Alnico V humbucking pickups, five-way switching and focus switch found on Professional and Standard models allow for ten musically inspiring pickup configurations.

These well-balanced guitars can provide all the necessary subtlety for jazz chordal passages yet add rock’n’roll grit and soaring blues too. As you can hear in the video, they also sound completely different from the Pacifica Professional on those solo lines.

The Wrap-Up

Chord substitution can be used to expand your songwriting chops, playing and compositional skills, and even improvisations.

When you think about the number of possible chord-progression permutations using just the seven diatonic chords, it’s quite astounding. Add in the ability to interchange some of those chords, and you are opening up your creativity to a whole new universe.

In Part 2, we’ll dive into the vast ocean of tritone substitutions, secondary dominants and modal interchange.

PHOTOGRAPHS COURTESY OF THE AUTHOR.

Check out Robbie’s other postings.