Lesson 28 Secondary dominant of the Subdominant
Part I - Introduction
Secondary dominants of the subdominant can be found in both Major and minor keys. However, not all dominant-type qualities are used. To see why, let's spell the V/IV in C Major, a fifth up from F (IV in C Major) is C. The root of the V/IV in C, is C. So the V/IV in Major keys is the tonic. To see it in a progression. Figure 1 shows IV - V/IV - IV in C Major.notice how the secondary dominant is just the tonic chord.
Fig.1 secondary dominant of IV in C Major.
Listen:
Here, in the minor key, the secondary dominant of iv is a C Major triad, which is not a diatonic triad in c minor.
Fig.2 secondary dominant of iv in c minor
Listen:
Here, notice the three common tones between the I and V/IV. This is great for voice leading because three of the voices do not need to move from the I chord to the third inversion V7/IV.
Fig.3 voice leading for V7/IV in C Major
Of course, it is also possible to use fully diminished seventh chords, and even the diminished triad as secondary dominants. They occur most often in minor keys. Although occasionally, they do occur in Major keys. Figure 4 demonstrates the vii°7/IV in major and minor keys
Listen:
Of course, it is also possible to use fully diminished seventh chords, and even the diminished triad as secondary dominants. They occur most often in minor keys. Although occasionally, they do occur in Major keys. Figure 4 demonstrates the vii°7/IV in major and minor keys
Fig.4 vii°7/IV in C Major and minor
Listen:
By far, the most commonly used secondary dominant of the subdominant is the V7.This is because of the voice leading. Notice that there are three common tones between the I and the V four-two
Fig.5 V7/IV in C Major
the V7/IV should read V four-two/IV
the V7/IV should read V four-two/IV
Listen:
Part II - Altered Scale degrees
The most indicative altered scale degree of the secondary dominant of the sub dominant is the lowered seventh scale degree. In minor keys, the most indicative altered note is the raised third scale degree.
Fig.6 voice leading for V7/IV in c minor
Listen:
The chord progression for the V/IV is:
Major
Major
I vi X/IV IV V I
minor
minor
i VI X/iv iv V i
