You might have heard about subsidiary chords and you were like “OMG”…. those must be heavenly chords…… i was once in those shoes before……without taking much of your time and bore you with long talks i will like to analyse subsidiary chords and prove to you that it is nothing difficult or special ……
In this post, we are looking at chords that are related to the harmonic function of any given triad (aka – “subsidiary chords”).
But before we do that, let’s breakdown the term harmonic function.
“Harmonic Function? What Does That Mean?”
Chord 1 in the key of C
In the major scale of C:
…the first scale tone is C.
Chord formation in thirds from C using the C major scale will produce the C major triad:
…(aka “chord 1.”)
Notice in all three cases, nothing changed about the C major triad. It was pretty much C, E, and G stacked together.
However, the C major that is chord 1 in the key of C, has a different function in the keys of G and F where it functions as chords 4 and 5, respectively.
We can’t play in the key of C major forever right?
If we move (or modulate) from C major to F major, we’ll still have a C major triad but with a different harmonic function. The C major triad in this new key (F major) would function as chord 5.
With all I’ve said so far, I hope you can understand that the harmonic function of a chord is simply what it’s used for and that largely depends on the key we’re in.
Subsidiary Chords – Defined
Subsidiary chords are chords that [share two pitches or more but most importantly] are related by harmonic function. – Jermaine Griggs
Any chord that can take the place of another and perform its harmonic function is known as a subsidiary chord. I want you to notice that the emphasis is on the term harmonic function.
So, when we’re thinking of a subsidiary chord, we’re probably thinking of a chord that can take the place of a given chord.
Here’s a direct question [to you]:
“If we are in the key of C, where the harmonic function of the C major triad is chord 1, what other triads can take up that harmonic function of being chord 1 and why?”
Here’s my answer…
“A minor triad can do the harmonic function of the C major triad as chord 1. Reason is, both triads have two notes in common”
C major triad:
…consists of C, E, and G while the A minor triad:
…consists of A, C, and E.
The common notes between both triads are C and E:
If you’re wondering how I arrived at A minor, don’t worry. In the next segment, I’ll enlighten you more by showing you the chord formation of the subsidiary chord using the given chord.
Chord Formation of the Subsidiary Chord
Even though there are four classes of triads – major, minor, augmented, and diminished, two are commonly used because of their stability.
In this post, we’ll be looking at the subsidiary chords of two stable triads – the major and minor triads and how to derive their subsidiary chords.
Subsidiary Chords For Major Triads
A major triad is built off the first, third, and fifth tones of the major scale.
If the fifth tone of a major triad is raised by a whole step, this would produce its subsidiary chord. Using the C major triad as an example, if the fifth of the C major triad (G):
…is raised by a whole step:
This would produce the first inversion of the A minor triad:
The A minor triad is the subsidiary of the C major triad.
Just in case it escaped your notice, we only raised the fifth tone of the C major triad (G). The first and third chord tones are the tones that the C major triad shares in common with its subsidiary chord.
Check out the major triads vs subsidiary triads in all 12 keys below:
C major vs A minor:
Db major vs Bb minor:
Let’s look at minor triads and their subsidiary chords.
Subsidiary Chords For Minor Triads
The minor triad is built off the first, third, and fifth tones of the minor scale.
Lowering the first tone (aka – “root”) of the minor triad would produce its subsidiary chord. Using the A minor triad as an example:
…if the root of the A minor triad (A):
…is lowered by a whole step:
This would produce the second inversion of the C major triad:
The C major triad is the subsidiary chord of the A minor triad.
Only the root of the A minor triad (A) is lowered. The third and fifth chord tones are the tones that the A minor triad shares in common with its subsidiary chord.
Check out the minor triads vs subsidiary triads below:
A minor vs C major:
Bb minor vs Db major:
B minor vs D major:
C minor vs Eb major:
C# minor vs E major:
D minor vs F major:
D# minor vs F# major:
E minor vs G major:
F minor vs Ab major:
F# minor vs A major:
G minor vs Bb major:
G# minor vs B major:
Let’s begin to round up…
The Circle of Fourths/Fifths
There are references and there are references.
In posts like this, rounding up without making reference to the musical clock is inappropriate. Therefore, permit me to show you in two minutes or less, how the musical clock can help you remember subsidiary chords.
circle of fifths 1
Using the musical clock, you can determine the subsidiary chords of any given major or minor chord.
Triads and their subsidiary chords are located in the same sector of this musical clock. For example, the C major and A minor triads are in the same sector in the 12 o’clock position.
Check these out:
12 o’clock position – C major is the subsidiary triad of A minor triad and vice versa.
1 o’clock position – G major is the subsidiary triad of E minor triad and vice versa.
2 o’clock position – D major is the subsidiary triad of B minor triad and vice versa.
If you keep going clockwise, you’ll encounter all major and minor triads and their subsidiary chords.
The importance of knowing subsidiary chords cannot be overemphasized.
Let me point out to you that the subsidiary chord of a given major triad is a minor triad while the subsidiary chord of a given minor triad is a major triad.
A given triad and its subsidiary may differ in quality, but the relationship between them is too close. They belong to the same sector of the musical clock and even share two notes in common.
Heck, one can even say that a given triad and it’s subsidiary are 66% identical. If you increase the quality of the chords to sevenths, the major 7th and subsidiary minor 7th are 75% identical (3 out of 4 matching notes).
Now that we’ve understood triads and their subsidiaries, we’ll meet again in a subsequent post where our focus will be on the application of subsidiary triads.