Secondary dominants are chords that are borrowed from a different key than the one the piece is currently in. They function as the dominant chord of a chord that is not actually present in the current key. This means that they create a temporary shift in harmony, leading the ear to expect a resolution to a chord that i...
How Secondary Dominants Facilitate Modulation
Secondary dominants are a powerful tool for composers to use in order to create smooth and convincing modulations, or key changes. This is because they create a sense of anticipation for a chord that is not in the current key. By resolving to this unexpected chord, the composer can effectively shift the key center of the piece.
For example, if a piece is in C major and the composer wants to modulate to G major, they could use a secondary dominant of G major, which would be D7. D7 is the dominant chord of G major, and it will create a strong pull to G major. When the D7 resolves to G major, the listener will perceive the change in key as natural and logical.
Types of Secondary Dominants
There are several types of secondary dominants, each with its own unique function and effect on the harmony of a piece. The most common types are:
- V of IV - The dominant chord of the subdominant chord. This type of secondary dominant leads to a resolution on the subdominant chord (IV). For example, in C major, the V of IV would be G7, which resolves to F major.
- V of V - The dominant chord of the dominant chord. This type of secondary dominant leads to a resolution on the dominant chord (V). For example, in C major, the V of V would be B7, which resolves to G major.
- V of VI - The dominant chord of the submediant chord. This type of secondary dominant leads to a resolution on the submediant chord (VI). For example, in C major, the V of VI would be A7, which resolves to Am.
Example of Secondary Dominants in a Modulation
Let's look at a simple example of how secondary dominants can be used to create a modulation from C major to G major. The following excerpt shows a typical progression in C major:
C major - G major - Am - F major
To modulate to G major, the composer could introduce a secondary dominant of G major, which is D7. This would create the following progression:
C major - G major - Am - D7 - G major
The D7 creates a strong pull to G major, making the modulation sound natural and smooth. The listener will be tricked into thinking that the next chord is going to be C major, but instead, it resolves to G major, effectively changing the key center of the piece.
Why Secondary Dominants are Effective
Secondary dominants are effective tools for modulating for several reasons:
- They create a sense of anticipation and tension. The fact that they are not in the current key creates a feeling of instability and expectation, which is resolved when they resolve to the target chord.
- They provide a smooth transition between keys. Because they create a connection between the current key and the new key, they make the modulation sound natural and logical, rather than jarring or abrupt.
- They can add variety and interest to the harmony. By introducing a different harmony from the current key, they can add color and depth to the music.
Conclusion
Secondary dominants are a powerful tool that composers can use to create smooth and convincing modulations. They are a versatile tool that can be used in a variety of ways to create a variety of effects. By understanding how secondary dominants work, composers can use them to create music that is both interesting and harmonically satisfying.