Secondary Dominant Chords | Hub Guitar

Secondary Dominant Chords

A dominant chord creates a gravitational “pull” towards its tonic chord. There are several factors that create this relationship. While we can analyze this effect and come up with a reason for it, the real reason it works this way is that we expect that it will. This expectation comes from many hours listening to music over a lifetime.

Let’s consider the cadenceA resolution, or feeling of finality, created by moving from a strongly tense and unstable chord, to a stable one. Usually supported by the notes in the melody as well. The most common cadence is V–I. between V7 and I, in the key of C major.

Note: all of the chords above are from the notes of the C major scale. This is important.

When the G7 chord arrives, we can hear a tension that will be resolved when the C chord arrives. Why does one chord make us “expect” to hear another one next?

Resolution of Dominant Chords

The G7 chord (left) has the notes G, B, D, F. The Cmaj chord (right) has the notes C, E, G.

As you read each of these points, make sure to look for them in the example before you move on to the next.

How the chord resolves

  1. The tone B “wants” to resolve up to C, as it usually does. Since it’s only a half step away, we expect it to.
  2. The tone F “wants” to resolve down to E for the same reason.
  3. The upper structure of the chord: B, D, F is a diminished triad. This unstable sound is restless and “wants” to go somewhere more stable.
  4. The movement between the bass note G and bass note C is a perfect fifth, creating a strong sense of finality.

This type of chord movement between V and I is the basis of modern music. Popular songs consist mostly of V and I chords, with IV being popular as well. In more complex music, we can consider this cadenceA resolution, or feeling of finality, created by moving from a strongly tense and unstable chord, to a stable one. Usually supported by the notes in the melody as well. The most common cadence is V–I. to be a sort of punctuation, like a period—or even an exclamation mark. It signals a halt to motion, a point of rest.

Borrowing More Dominant Chords

A cadence creates a strong sense of tonalityThe key in which a piece is played, and the relationships of the notes to each other, and most especially to the tonal center.. The G7 chord is not like the C chord, but they complete each other. When the G7 chord appears, it sounds natural that a C chord will follow. The relationship between V7 and I is so powerful that we can actually borrow a V7 chord to use even when it doesn’t belong in the key, and it has the same function. Let’s consider the example again:

If we want to strengthen the Amin chord, we can put an E7 chord in front of it. The E7 does not belong in the key of C, but we can borrow it any way because of the strong relationship it has with the Amin chord. This creates an effect called tonicizationA method of composition which, usually temporarily, gives rise to the feeling that the tonal center has changed. For instance, the VImin can be tonicized by preceding it with the V/VI secondary dominant chord..

Notice that the “E7” chord does not belong in the key of C. It contains the tone G♯ which is not in the key. But this is why it works: it is new and unexpected, and it resolves strongly to the Amin chord, which does belong.

This is useful for two reasons:

  1. It gives composers a chance to use G♯ that otherwise would not sound good in the key. Now that it’s supported by a chord, it can also have a place in the bass or the melody.
  2. It is a tool that can make the Amin chord sound bigger and more important.

Secondary dominant chords are popular in all forms of music. There’s a secondary dominant in the national anthem of the United States. Listen to the song during the lyrics, “that our flag was still there” and you will hear an unusual note on the word “still”. This note is the third of a secondary dominant chord resolving to the V chord of the key. In the melody, you hear it resolve up to the fifth of the key. Secondary dominants have become less used in American pop music, but overall they are quite common.

Put It Into Practice:

With a pen and a piece of paper, fill out the following chart for Secondary Dominants in the key of C major.

Chord Function Chord Name Resolves To Contains Chromatic Notes
V of vi E7 Am E, G♯, B, D G♯
V of V        
V of IV        
V of iii        
V of ii        

Key Questions

  • Why is there no “V of I”?
  • Why is there no “V of vii”? (Try it for yourself. Note: answer simpler than it seems.

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