Secondary Dominants: Introducing the Seventh Chord

With the exception of the tricky diminished vii (which we’re ignoring for the time being), in this series so far, we’ve played around with all of the core major key chords. With these under your belt, you should be able to

  1. establish a sense of home,
  2. explore the immediate neighborhood,
  3. play with tension and release, and
  4. create depth and surprise with shifts between light and shadow.

Not a bad start.

But now it’s time to get even more adventurous. Remember how the V builds a sense of expectation for the I? This is a simple but powerful device. And the exciting thing is, it can be used to emphasize other chords as well.

Say you want to place the emphasis on the V itself. One method for accomplishing this is to begin from what’s called the V-of-V. The V-of-V is not one of the core diatonic chords we’ve covered so far. It comes from outside the home key. And it’s known as a “secondary dominant”.

For the next several entries, I’m going to discuss a variety of secondary dominants and provide exercises you can use to integrate them into your songs. But before we can get to that, we should go back to the old familiar V-I progression, since it’s the prototype for the secondary dominant progressions.

In particular, we need to look at a method for making the magnetic pull of the V even stronger. We do this by turning it into a seventh chord.

Since my emphasis here isn’t on the details of music theory, I’m not going to go into the nitty gritty about what makes a chord a seventh chord. For our purposes, what’s important is that it’s a modification of a more familiar chord that gives it a new feel. We’ll be looking at one seventh chord in particular: the V7 (in the key of C major, that’s G7).


Let’s start simple to introduce the sound of the V7. Get comfortable playing a familiar I-IV-V progression. Come up with a melody and repeat it a few times.

Now, as you round the IV, play a V7 instead of a V. Notice the difference?

Notice how it forces you to change your melody? As you move from the V7 to the I you should feel an even stronger pull than normal. You’ve just tapped into a supercharged magnet.


Now that you have a sense for the difference changing V to V7 makes, it’s time to experiment. Try coming up with a song using any of the methods we’ve explored so far. Use the ii-V-I magnetic tunnel to get back to home. But instead of ii-V-I, play ii-V7-I. Hear the difference?

What happens if you change from V-V7 within a phrase? What does ii-V-V7-I sound like?

What about a deceptive cadence from V7-vi instead of V-vi? Or what about ending a shadowy chorus on the V7 in order to supercharge the return to the verse?

The best way to get a feel for the V7 is to try it in as many contexts as you can. It’s not a surefire method. Sometimes it will break the feel of your song. Sometimes it will sound awkward. But with a little practice, you should find a place for it.

Next: II7 (V of V): Portal to Another World