5. It’s All Relative
In the first three blogs we went over the terms and their meanings and how chord harmony works, and then we took a slight side trip to talk about how it works on guitar. In this blog we will go back to talking about the major key, chord harmony, and introduce the relative minor key.
- The I, IV,and V are major chords
- The ii, iii, and vi are minor chords
- The viiø is a diminished chord
The Relative Minor
There is a relationship between major triads and minor triads. Let’s look at C major where the scale tones are C D E F G A B. The sixth tone in the C major scale is A and when we harmonize a triad based on the A (in C major) we get an A minor triad. These two chords share two common chord tones, C and E, where the Root and major 3rd of the C major chord are the minor 3rd (C) and 5th (E) of the A minor chord. This tonal similarity connects the sounds of the C major and A minor chords in a way that has been named the relative minor. C major is happy sounding (major 3rd) and A minor is sad sounding (minor 3rd).
The really neat thing about this relationship is that a major key and the relative minor key share the same musical notes in their scales, but they have a different tonal center (Root tones). To identify the scale degrees and positions of the tones of the relative minor key, we move the Root note from the Root tone of the major scale to the 6th tone and it becomes the Root of the relative minor scale. Likewise, to find the relative major Root of a minor key, we move the Root tone to the 3rd tone of the minor scale and it becomes the Root tone of the major scale. In other words, from the major scale, the movement up a major 6th interval (C up to A) when inverted is a movement of down a minor 3rd (C down to A).
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For Example:
- C Major - C D E F G A B
- A Minor - A B C D E F G Or Scale Degrees*
- Major scale - R 2 3 P4 P5 6 7
- Minor Scale - R 2 ♭3 P4 P5 ♭6 ♭7
As noted above, the I chord shares two notes with the vi chord. For example in the key of C major, the I chord is C major (CEG) and the vi chord is Am (ACE). We can see that the chord tones C and E are in both chords. The presence of these two common chord tones gives the two chords a similar harmonic function. We call the vi chord the relative minor to the major key I chord. Below is a look at some more examples of major key I chords and their relative minor chord relationships:
| Key | C | D | F | G | A | E |
|---|---|---|---|---|---|---|
| I | C (CEG) |
D (DF#A) |
F (FAC) |
G (GBD) |
A (AC#E) |
E (EG#B) |
| vi | Am (ACE) |
Bm (BDF#) |
Dm (DFA) |
Em (EGB) |
F#m (F#AC#) |
C#m (C#EG#) |
| Notes in Common | CE | DF# | FA | GB | AC# | EG# |
Major and Minor Diatonic Relationships
Above we noted that the major scale and its relative minor scale have the same musical tones, but Rooted on different tonal centers. Similarly, we have the same chords in the relative major and minor keys, but in different functional harmonic roles (more on this in a later blog).
As shown above, a major triad chord and its relative minor triad chord share two chord tones which means only one note is different between them. That is the 5th of the major triad moves up one whole tone to the Root of the relative minor triad. Or, the Root of the major triad moves down a minor 3rd to the Root of the relative minor.
On the guitar we see both happen when going from a major C-shape or major G-shape to their relative minors. In a C major chord (C-shape), the Root (C) moves down a minor 3rd to the Root tone (A) on the fifth string, and the 5th tone of C (G) moves up a whole tone to the Root (A) on the third string to form the relative A minor triad (see diagram below). A similar movement happens where the Root of the G major (G-shape) moves down a minor 3rd to the E Root on the sixth string and 5th (D) moves up one whole tone to the (E) Root on the fourth string to form an Em chord, the relative minor of G major (see the diagram below).
Ionian and Aeolian Modes
(A Glimpse of The Bigger Picture)
The major scale is also know as the ionian mode. This is the first “harmonic mode” we learn to use. The second mode we learn is the relative minor also know as the aeolian mode. The aeolian mode is also known as the natural minor scale. There are two other minor chord scales, the harmonic minor, and the melodic minor. We will talk about them more in the future.
Modes have a very creative use in songwriting and in making music, but the way modes are usually taught is more academic and less musical. You can hear modes in almost all genres of music. You may be experiencing a modal sound when you come across a very cool chord progression that otherwise doesn’t make sense. We will discuss all seven modes down the road, but for now we will stick with the ionian and aeolian.
Warning: Do not get wrapped around the axel on the terms or memorizing this scale versus that scale. It is much more important to learn the different sounds, feelings, or emotions available from the different chord relationships from each mode.
Minor Diatonic Chords
In the second blog in this series we discussed chord construction and harmony based on the major scale. The same chord harmony theory works for all the modes including the aeolian mode. You start with the Root of the key and build chords based on the diatonic third intervals.
The minor (aeolian) scale formula is Root W H W W H W W (W = whole tone and H = half tone). This produces a different chord arrangement from the major scale where the natural minor chords follow the scheme shown below:
- The i, iv, and v chords are minor
- The III, VI, and VII chords are major
- The iio is diminished
Just as the C major and A minor have the same notes, they also share the same chords. However, as we will learn in the next few blogs, these chords have a different harmonic function in each mode. Please see the table below for the chord-type similarities and placement in the major and relative minor keys of C major and A minor.
| Major | C | Dm | Em | F | G | Am | Bo |
|---|---|---|---|---|---|---|---|
| (Ionian) | I | ii | iii | IV | V | vi | viio |
| Minor | Am | Bo | C | Dm | Em | F | G |
| (Aeolian) | i | iio | bIII | iv | v | bVI | bVII |
The chords and tones for the A natural minor scale are shown in the diagram below.
While we are looking at the natural minor diatonic chords let's look at the first extended chord forms too. The diatonic 7th chords for the A natural minor scale are shown in the diagram below.
Closing
In this blog we have learned the major key has a relative minor key (and a minor key has a relative major key too). The musical notes (scale tones) for the major key and the relative minor key are identical, but the relative minor is rooted on the 6th scale degree of the major key forming a different tonal center. The major key is based on the ionian scale and the relative minor key is based on the aeolian scale, also know as the natural minor scale.
We will learn more about the relationship of other scale types and related chord harmony down the road.
In the next blog (or two) we will look at functional harmony which will lead us to finally beginning the discussion of chord progressions.
