An important music theory tool for songwriters, composers and musicians in general is the secondary dominant. This tool alone can turn a boring chord progression into a masterpiece or number one hit song. I invite you to join me on a journey of pimping a simple chord progression and turning it into complex and professional harmony.
I will take you from a simple chord progression like this:
C Am F G
To a much more sophisticated and professional sounding chord progression like this:
C E7/B Am C7/G F F#dim G7
And the only tool we really need is: the secondary dominant. Let’s go!
The Starting Point – 50s Progression
We will start with a simple and famous chord progression from the 1950s: the 50s progression. It has been used by countless songwriters and the chords are the following in C major:
C Am F G
Very simple, very uneventful. Now you could totally use this chord progression as is and compose a song from it; but I like to make things a little more unique, shiny and sophisticated. Pimping simple chord progressions like the 50s progression makes a song stand out and increases the chances of it becoming a number 1 hit song; and it is just more fun and more interesting to listen, sing and play to!
We apply a lot of music theory to such a simple chord progression, but in this article I want to focus on one specific music theory tool: the secondary dominant.
Let’s first get to know this tool, before we apply it to our chord progression.
The Tool – Secondary Dominants
A secondary dominant is not as scary as the term might sound. Let’s tackle the jargon one by one.
A dominant is a chord with a lot of musical tension. Dominants scream to be resolved to a chord with very little tension (which we call a tonic chord). Dominants achieve this by including many strong leading tones towards the notes of the tonic chord.
The dominant probably everybody is familiar with is the chord on the fifth scale degree of a major scale (V7). In C major, this is the chord G7. The G7 has a strong pull towards the C major tonic chord and every listener kind-of expect a G7 chord to be followed by a C major chord.
Although there are more chords that can create dominant-like tension, only this chord is usually referred to when talking about “the dominant”. The dominant is a perfect fifth above the tonic chord it targets (i.e. wants to resolve to): G is a perfect fifth above C. We can also call this the “primary dominant”.
So much for the dominant. Now to the second part of the jargon.
A secondary dominant chord is dominant chord that leads to a chord OTHER than the tonic of the key. So any dominant chord leading to Dm or F in the key of C major is a secondary dominant. It’s just a dominant leading to a “tonic” which is not the tonic of the key C major.
A secondary dominant still sits a perfect fifth above its target chord and thus resolves a perfect fifth down.
Let’s take the chord of F major, which is a chord in the key of C major, but is not the tonic. To find the dominant chord leading to this F major, we simply jump one fifth above F and then play a dominant chord on that note. A perfect fifth up from F is C – and to make it a dominant chord, we play it as C7. Great, you have just found a secondary dominant leading to the F major chord in the key of C major!
Now let’s apply this music theory knowledge to our real world chord progression.
Hands-on – Apply Music Theory to the Real World
Let’s look at our initial chord progression again:
C Am F G
You might already spot the (primary) dominant in there: the G. We could just make this more “dominanty” by adding the minor 7th while we’re at it:
C Am F G7
This dominant wraps around to resolving to the tonic chord C major at the beginning of the chord progression. But now to the meaty part – let’s apply some secondary dominants!
The second chord Am chord be preceded by a dominant chord strongly leading to it. The dominant chord leading to Am is a perfect fifth up: E7. So let’s insert E7 here (and at the same time shorten the C major a little to make room):
C E7 Am F G7
This chord progression sounds much more interesting and has a stronger forward momentum. And by adding the E7 we introduced a non-diatonic chord – a chord with notes that don’t belong to the key of C major! In fact, all secondary dominants are non-diatonic. In the case of E7 we now have a G# note which is totally not from the key of C major. These non-diatonic notes do not only add nice leading tones towards the target chord, but also add a new sonic color to the progression.
Let’s move on to the next chord F.
The F major could also use a preceding dominant chord leading to it. Again we go a fifth up from F and find the dominant chord: C7. Again we shorten the Am a little, so we can fit in the C7 in the same bar:
C E7 Am C7 F G7
Wow, another non-diatonic chord (introducing the note Bb). Now the chord progression really begins to roll with a lot of forward momentum. This Momentum is created by the natural pull of dominant chords.
On to the last chord in the progression: G7. Again, we go up a perfect fifth and find the dominant chord: D7:
C E7 Am C7 F D7 G7
That gives us a dominant chord leading to a dominant chord! Now in that case many people would actually use a “pre-dominant” chord leading to the dominant chord. The most common pre-dominant chord would be a minor 7th: Dm7 G7. You might recognize a ii-V cadence here ;). Nevertheless, we will stick with the dominant chord D7 for this example.
Now this chord progression has a pretty strong forward momentum already. But there is one little thing that drags a little:
Have you noticed how the bass line is now jumping around pretty frantically? It’s moving up a third to E, then down a fifth to A, then up a third again to C, then down a fifth … . While this bass line still works, we can smoothen the ride of the chord progression – and therefore increase the momentum even further – by taking out some of the leaps and using small steps (half-note or whole-note steps) in the bass.
The bass doesn’t always have to play the root of a chord – especially in harmonically weaker spots like the 2nd, 4th or 6th chord. The bass will do fine with any note from the chord. So to make the move from C to E7 to Am smoother, the bass could just move down in steps from c to b to a:
C E7/B Am
This makes the bass movement much more singable and melody-like. And this greases our chord progression so that it can move so much more elegantly. Let’s continue this trick for the rest of the chord progression:
C E7/B Am C7/G F D7/F# G7
Awesome, now the bass almost has its own little melody.
We’re almost done, but let me give you a little bonus tip here.
Bonus – Diminished Passing Chords
If you play the D7/F# chord in the new chord progression, you might notice that it almost looks like an F# diminished chord:
D7/F#: f# a c d
F#dim: f# a c d#
Yes, in fact you can replace the D7/F# chord with an F#dim chord! Actually, the diminished chord between the 4th and 5th degree of the major scale is commonly used to smoothen the transition to the dominant chord.
By adding the additional non-diatonic note of d# (or enharmonic eb), you add yet another leading tone towards the target chord G7. That new F#dim chord could also be interpreted as an altered secondary dominant chord: D7b9/F#. So without much effort, you crowned this chord progression with an altered secondary dominant – yeah!
C E7/B Am C7/G F F#dim G7
The Result – What you have Learned
We transformed the simple, rather uneventful 50s chord progression:
C Am F G
Into this sophisticated and professional sounding chord progression with significantly more forward momentum, non-diatonic notes and even a fancy diminished chord:
C E7/B Am C7/G F F#dim G7
We could do this using only one single music theory tool: the secondary dominant.
You now have this tool of secondary dominants in your arsenal as a songwriter. Practice to use it and apply it to your next composition!
What to do next
To practice secondary dominants, look at songs you like or songs you wrote. Try to sneak in as many secondary dominants as you can. Remember, this is just for practice. For real compositions, you usually want to dial back the excessive use of secondary dominants in front of every single chord a little. Nevertheless it is good practice to at least be able to know and play all the possible secondary dominants.
Once you have a few nice dominants to increase your songs momentum, try to use chord inversions to make the bass line more melodic. This takes practice, but it can lead to an even more sophisticated and professional sound.
And most of all: have fun using this music theory tool, keep writing your songs, and enjoy making awesome music!