Understanding Secondary Dominants in the Key of C

So earlier we talked about the fact that in the key of C, we had an E7 chord taking us to A minor. This is a secondary dominant on the 3, which would normally be E minor 7.

You may have noticed there's another secondary dominant in this tune, which is the A7 chord. In C, this would normally be a minor 7. This chord takes us to D minor, a perfect cadence in D minor.

Minor Chords in A Major Key

• The minor chords in the A major key are often turned into dominants.
• You normally get a dominant chord on V and nowhere else.
• If you have it anywhere else, it's referred to as a secondary dominant.

Examples of Secondary Dominants

• In the key of C:
  • The II chord could be D7 (if it was a secondary dominant).
  • The III chord could be E7, which is what's happening here when we go to A minor.
  • The sixth chord, A minor, could be a 7 if we want to go to D minor.

These three minor chords on 2, 3, and 6 are often turned into dominant chords just to spice up the harmony a little and create perfect cadences that lead us into closely related keys.

• In this case, E7 takes us to A minor, and A7 takes us to D minor.

The Bigger Picture

However, it's important to note that we're not really going to the key of D minor. Instead, D minor is just part of a 2-5-1 in the key of C.

These extra notes, or chromatic notes, outside the key give the harmony much more color. It's important to be aware of them. Despite these variations, we are not departing from the key of C. We're still using a diatonic cycle, but it's been spiced up a little.

Recap

To recap, in the first eight bars of "Flammy to the Moon":

• We have an E7 in bar 7, which is a secondary dominant, taking us to A minor, the relative minor.
• In the second half of the sequence, we have an A7 in bar 12, which strengthens the change to D minor, still part of the 2-5-1 in C major.