6. Three Chords and the Truth!
It was Harland Howard, a prominent Nashville songwriter, who described country music songwriting as “three chords and the truth.” Well the three chords that are most commonly used in songwriting are the I, IV, and V chords of a major key. You will find some combination of the I, IV, and V chords in blues, country, folk, traditional, polka, zydeco, and many world music forms too. Of course, the other chords of the key also get used, and each chord has an expressive harmonic function in a chord progression.
In this blog we will begin exploring functional harmony, chord progressions, harmonic cadences, and diatonic chord substitutions.
Functional Harmony
Now we discuss the important concept of Functional Harmony. The functional relationship between the I, IV, and V chords is one of stability (home base) for the I chord, some instability (leaving home on a journey) for the IV chord, and unstable (wanting to get home) for the V chord. In other words, the I chord is stable, the IV chord adds some tension, but the V chord adds strong tension and you need to go home for a release of the tension. The table below shows the function of the I, IV, and V chords and the other diatonic chords. Note that there are a few different camps of music theory terminology, so you will find other terms or classifications used. I’ll stick with the simpler approach.
| Chord Functional Harmony | ||
|---|---|---|
| Function | Degree | Substitute |
| Tonic (Stable) |
I | vi, iii |
| Subdominant (Less Stable) |
IV | ii |
| Dominant (Unstable) |
V | vii0 |
You can use the relationships between the tonic, subdominant, and dominant chords to frame the melody that supports your lyrics. Sometimes it works the other way round, or from the middle out, but movement from a tonic chord to any other chord usually adds some tension or instability. Moving from the dominant chord or from a subdominant chord to the tonic chord brings resolve, a release of tension, and stability. This concept is a very important one for composing music and writing chord progressions that support the melody and lyrics. I’ll let Ian O'Donnell’s YouTube video give you more detail.
The concept of functional harmony works very well for chord progressions in major keys, but these relationships become less certain when composing in minor keys. Of course writing in a minor key implies some level of uncertainty. The overall concept of functional harmony and chord function - the concept of home, tension, and release by returning to home - is very strong and very important. In our lyric writing and our melody compositions, we build the emotional backdrop though choosing chords that complement the melody. We choose chords that build tension when the lyrics become intense, and come to the tonic chord to find resolve when the lyrical phrasing reaches stability, a conclusion, or a finality.
But let us look at the I, IV, and V chords again and do more exploring.
Common I, IV, and V Chord Progressions
As we discussed in the previous blog, the first chords you likely learned on the guitar were the first position chords or Cowboy chords. Also, the major key I, IV, V chords are the first we learn on piano or any instrument capable of making chords. Thus, the first songs you learned probably used the I, IV, and V chords in some arrangement. For reference let’s see examples of chord progressions in a few common major keys:
| Major Key | I IV V I | I V IV I | I IV V vi |
|---|---|---|---|
| C | C F G C | C G F C | C F G Am |
| A | A D E A | A E D A | A D E F#m |
| G | G C D G | G D C D | G C D Em |
| E | E A B E | E B A E | E B A C#m |
| D | D G A D | D A G D | D G A Bm |
Pick up your guitar or ukulele, sit down at the piano, or grab your mandolin and play through these chords, in an 8 bar or 12 bar arrangement. As you do, start thinking in terms of tonic, subdominant, and dominant chords as you play through each example. Note how each one “feels” as happy, resolved, or has a little mystery or open ended (more discussion below with cadences).
I will also challenge you to go one step further and refer back to the “Functional Harmony” table presented earlier and experiment using the substitute chords shown in the last column for their functional partners (substituting the minor ii chord for the IV chord for example). You may write a new song or finally discover that chord you have been looking for in that song you have been working on for four months.
Cadences
The relationship of the two chords ending a phrase or a section are likely one of the four harmonic cadences shown in the table below. There are several other cadences, but we will look at these four for now.
| Cadence | Progression | Authentic | V → I |
|---|---|
| Plagal | IV → I |
| Half | Any → V |
| Deceptive | V → Any |
The most satisfying cadence is the movement of the V chord to the I chord, which is call an “Authentic” or a “Perfect” cadence. This has a strong resolve as you move from the dominant V chord to the tonic I chord. This feeling is even stronger if you use the V7 or dominant seventh chord then resolve to the tonic I chord.
The Plagal cadence is movement from the subdominant IV chord to the tonic I chord and is also considered a perfect cadence. The Plagal cadence is probably best known as the “Amen” cadence as it is used heavily to end sections in hymnal compositions. The movement from the subdominant IV chord to the tonic I chord provides resolution, but from a point of less tension than the movement from the dominant to the tonic.
The “Half” cadence is one that leaves you wanting to keep moving. The half cadence is also known as the imperfect cadence. Resolving to the dominant V or V7 chord is more like a comma than a period. That is you want to keep moving to find resolution.
The deceptive cadence is just as it’s name implies, deceptive. When you move from the dominant V or V7 chord to any chord (other than the tonic I chord) is unexpected and leaves you feeling unstable or maybe mysterious.
Below is a video that gives some audio examples of each of the four cadences discussed above along with some additional explanations of cadences.
Closing
So, this article presented some important concepts about functional harmony and harmonic cadences. We talked about the I, IV, V chord progressions and substitutions using the subdominant ii chord in place of the subdominant IV chord, and substituting the iii or vi chord for the tonic I chord to explore functional harmony.
I want to encourage you to take what you have learned over this blog series and begin to analyze your own songs, or other songs. When you listen to a song, think about the chord progression and how the melody and the mood of the lyrics work together to put you in a place, a time, a frame of mind. In time, you will find that missing chord, the substitution to emphasize a line and bring the listener into your song.
In the next blog we will dig a little deeper into chord substitutions, discuss parallel minor chord substitutions, and a few turnarounds.
