Secondary Dominants

Definition: A secondary dominant is a dominant functioning chord of a major or minor chord in a key other than tonic.

Let’s start our discussion of secondary dominants by looking at an old(er) song, “Easter Parade” (1933) by Irving Berlin. (The tune was originally written in 1917 and made famous later in a movie by the same name; see audio here.) Below is one version of the chords for the first part (and the ending) of this song:

First, let’s try analyzing what we can with roman numerals.

In the key of Bb major, we can analyze most of the chords, but two of the chords (see blue and purple highlighted chords) are not diatonic in Bb major.

Using jazz/pop symbols for analysis, we do not have indicate these chord any differently than the other chords – just indicate root, quality and what note is in the bass (if different from the root) – so our analysis could stop here. However, it is good to know that these chords are not diatonic and how they function. So, let’s proceed.

Both of these chords are major-minor 7th chords (dominant 7th chord or V7) but are not the dominant chord (V) in the key of the piece (Bb). Both chords contain notes outside the key of Bb; the Bb7 will have an Ab in it and C7 has an E natural.

Since these chords are not diatonic (in the key), we do not know (yet) what roman numeral to give these chords.Let’s look at the C7 in measure 7. (We will come back to the Eb much later.)

In the key of Bb, a seventh chord on C would be a minor seventh chord (a C-7). Therefore, the last three chords, diatonically, would be:

However, the C chord in our piece is a major minor 7th (C7), a dominant seventh chord:

The C7 chord, being a major-minor 7th chord, will sound like a V7 chord – but not a V7 in the key of Bb. Instead, it will sound like a V7 chord in the key of F.

Embedded in the longer progression, the C7-F progression will still sound like a V7-I progression, but the F chord will become an F7, a V7 in the key of Bb and will resolve to Bb (I in the key).

The F7 is the primary dominant in the key of Bb. The C7 is still going to sound and act like a V7 (but of F). This C7 is a secondary dominant.

A secondary dominant is a dominant functioning chord of a major or minor chord in a key other than tonic.

Note: In our version of this progression (from the song “Easter Parade”), the F triad is omitted and replaced by the F7 chord.

To show that the C7 is V7 of the F7 (the secondary dominant), it is labeled as V7/V – meaning the chord is functioning as a V7 in the key of (/) F major – the V of Bb.

Going back to “Easter Parade,” the final roman numeral analysis of the last few measures would be:

Remember that a secondary dominant can be defined as a dominant functioning chord of a major or minor chord in a key other than tonic. A V7/V (as in the above example) is just one example of a secondary dominant. There are many different chords that can be secondary dominants (as the Eb7 chord in the first line of “Easter Parade”) which will be explained more on the page Secondary Dominants – General.