CHAPTER 7 - SECONDARY DOMINANTS

Secondary Dominants are dominants of chords other than the tonic, and they are very important in tonal harmony, as they enrich it significantly. In this chapter we will deal with their definition, construction and use in 4 voices.

1. DEFINITION.

- So far, we are familiar with the main dominant chord of the key (V), which normally precedes the tonic (I).

- However, other degrees than I can also be preceded by a somewhat special dominant, which is called a "secondary dominant".

- It is referred to as "V of the (degree)" which it precedes, although it is notated as V / (degree).

Im. 7-1

- As you can see in the example, which contains a secondary dominant of the II degree, this secondary dominant:

- Precedes the II

- Is called "V of the II", although it is notated as V/II

2. CONSTRUCTION OF A SECONDARY DOMINANT.

- Secondary dominants usually have a 7th. We will build them, for now, as dominant 7th chords. To build them, we have to think of the dominant of the (major) key of the degree they precede.

- Let's illustrate this with an example. We want to know what is the V of the VI in C Major:

1º - The VI degree in this key is an A minor chord.

2º - We have to think what is the dominant (V) with the 7th in the key of A (Major).

3º - The answer is a chord formed by the notes E-G#-B-D (E dominant 7th chord)

Im. 7-2

- Notice that a secondary dominant ALWAYS has one or more accidentals, because it is basically a dominant belonging to ANOTHER key. This is why they are said to be chromatic chords (the chords belonging to the key are diatonic).

3. LOCATION IN THE BASIC HARMONIC SYSTEM & UTILITY.

- What we know, until now, as the regular order of chords in tonal music, which we have called the Basic Harmonic System (described in Chapter 3), is still preserved when using secondary dominants.

- At any moment, we can simply make any degree, other than the tonic, be preceded by its secondary dominant.

- For example, the following harmonic progression:

I -  VI  -  II  -  V  -  I

can be transformed into:

I  - V/VI  - VI  -  II  -  V/V -  V  - I

(we could also have placed a secondary dominant before the II degree)

- Secondary dominants are very useful to ENRICH the Basic Harmonic System. Without them, it may become somewhat repetitive. Therefore, it is very useful to add, from time to time, a secondary dominant. This will greatly enhance the harmonisation.

- On the other hand, a secondary dominant serves to EMPHASISE the chord it precedes, as if it were announcing it. Listen to some examples and pay attention to this aspect as well.

4. APPLICATION IN 4-PART WRITING.

- As secondary dominants are, for the time being, dominant 7th chords, everything described in Chapter 5 regarding these chords applies here too. It should be remembered, as it was stressed in that chapter, that dominant 7th chords will preferably be used in inversion.

- In relation to notation, we use the same figures as those for the regular dominant 7th chord. We can observe all these aspects in the following example.

Im. 7-4

- With regard to the exercises, if we depart from a given soprano or bass, we must treat any accidental that does not belong to the key as a secondary dominant. 

- However, in order to use secondary dominants, it is not necessary to restrict oneself to the presence of notes with accidentals in the melody or the bass. We can use secondary dominants at any time as long as we respect the rules which have been discussed. This will add colour and richness to our exercise.

5. SUGGESTED EXERCISES.

- Harmonize the following soprano lines in 4 voices, placing secondary dominants on the spots marked with *.

- Harmonize the following soprano line in 4 voices, making use of secondary dominants where appropriate.

4.  Write a harmonic structure with the following features:

- Key: Bb major

- Time signature: 4/4

- Form: 2 phrases of 6 measures (12 measures in total)

- Cadences (at the end of each phrase): Half cadence, Perfect cadence

- Harmonic rhythm: Half notes, with an acceleration before the cadences.

- Use at least 3 secondary dominants