5.3 Predominant Seventh Chords

In unit 5.1, we talked about how to use triads to develop the predominant section of a chord progression. Can we also use seventh chords in the predominant section? Absolutely! 

Before diving into seventh chords, let’s first remind ourselves what the primary predominant chords are and how they are used in music. 

There are several different chords that can function as predominant chords, depending on the specific context and musical style. In tonal music, the ii chord (the minor chord built on the second scale degree of the key) and the IV chord (the major chord built on the fourth scale degree of the key) are often used as predominant chords.

Predominant harmonies (ii and IV) – and their minor keys equivalents- are so named because they LEAD to the dominant. Just like dominant chords have a strong tendency to resolve to the tonic, predominant chords have a strong tendency to move towards the dominant. It is also easy to move from tonic chords to predominant chords. 

That is, phrases that were just I-V-I can now become I-ii-V-I or I-IV-V-I. Think of the predominant section of a phrase as a preparation of the dominant. Its function is to expand the basic phrase going from T-D-T to T- PD- D- T. This type of phrase is more used than T-D-T.

You’ve probably heard this progression several times. If you have a piano or a keyboard near you, play a I-IV-V-I progression really quickly. Have you heard these harmonies before? Chances are, it sounds familiar! The I-IV-V-I progression is really common in both popular and classical music. 

Let’s talk about how to use the IV and the ii chords in chord progressions, and how to incorporate proper voice leading into and out of the predominant section. 

The subdominant chord (the IV chord in Major, and the iv chord in minor) is very commonly used as the first predominant chord in a chord progression. Why? Because it is a perfect fifth below the tonic, meaning that if you are moving down the circle of fifths, you will end up going from the tonic to the IV chord. 

Using the IV chord also makes it easy to move stepwise when moving from the tonic to the subdominant. Take, for example, a tonic chord in the key of F Major. The I chord will have the notes F-A-C. And, the IV chord will have the notes Bb-D-F. We retain the tonic note F, which allows us to still hang on to some of the tonic-centered sounds in the chord progression, but we also move away from the tonic section of the phrase. 

Let’s look at an example derived from one of the past AP Music Theory exams: 

Notice that the iv chord is inverted to a iv6 chord in first inversion. Let’s walk through a scenario in which the chord was in root position. This is perhaps more common than a subdominant chord in first inversion, especially if we were in Major key, because the root position emphasizes the predominant function of the IV chord. 

If we had left the iv chord in first inversion, then we would have to put the C in the bass. Since we don’t want to move from a perfect fifth to a perfect octave we would have to put an E in the tenor. It makes sense to leave the alto voice as a G, and let the soprano voice be a C so we can double the root.

While IV chords are great as predominant chords, sometimes we just want to spice things up a little bit and add some more harmonic interest. It would be quite boring if all of the phrases in a piece were just I-IV-V-I or I-IV-vii-I phrases. Another great option for a chord with a predominant harmonic function is the supertonic chord, which is ii in Major and iio in minor.

 Just like the viio chord is a weaker substitute for the V chord in the dominant section of a phrase, the ii chord is a weaker substitute for the IV chord. It is sufficient to have only a ii chord in the predominant section, but the ii chord also often comes after the IV chord to expand the predominant section. If you have both a IV chord and a ii chord in the predominant section, always put the IV chord first! 

As a triad, ii chords in the predominant section are usually in first inversion (ii6 and iio6). In first inversion, the bass note will be the subdominant, which emphasizes the predominant function of the ii chord. If you want to emphasize the subdominant even more, you can also double the third in ii6 and iio6 chords. 

As you are figuring out now, contrary motion will help us most of the time, however, there are still rules we need to double-check when writing harmonies. When a predominant chord moves to a V⁷, the chordal seventh (the seventh of the chord) needs to be prepared by a common tone. In order for that to happen, you must choose carefully which chord is appropriate while keeping in mind that a V⁷ chord has 4 notes. To avoid parallel 5ths, you must always go in contrary motion and keep common tones when possible.

Why did we spend so much time reviewing predominant function triads in this section? Well, the short answer is that we can cross apply most of the things we know about predominant triads to predominant seventh chords. 

There are a few special cases we should talk about: 

Let’s start by covering the supertonic seventh chord. Usually, we see the ii7 chord show up in root position (ii7) or in first inversion (ii 6/5). 

Here are examples of this being done in both Major and minor:

When we want a stronger predominant, we prefer using a first inversion supertonic chord, because the bass will be the fourth scale degree (the subdominant) which will help us transition into the dominant section. However, ii7 chords in root position also provide a strong predominant harmony, especially when the ii7 leads to a V7 in a harmonic chord progression. 

In other inversions, the supertonic seventh chord might not have a predominant function at all. For example, the ii 4/2 chord is commonly used as a pedal tone to expand the tonic area of a phrase. For example, you might have a I-ii 4/2-I chord progression, which retains the tonic as the bass note, but allows the upper notes to change slightly, creating some harmonic interest in the tonic section of a phrase. 

However, the ii 4/2 can be used as a predominant chord. You will probably see it in a I-ii 4/2-V 6/5-I chord progression if it is being used as a predominant chord. 

🦜 Polly wants a progress tracker: Can you write a I-ii 4/2-V 6/5=I chord progression in Ab Major using proper voice leading? Remember to resolve tendency tones correctly! 

We usually don’t see subdominant seventh chords: it is a little rare to see a IV7 or a iv7 chord in music in the style of the Common Practice Period. However, if they do come up, they most likely will be in root position, and they are more common in minor than in Major. Here is an example;

In general, voice leading with seventh chords in the predominant section is quite similar to voice leading with seventh chords in other instances. Remember that in root position, it is okay to remove the fifth in seventh chords. This is also true for predominant seventh chords. 

If you do choose to remove the fifth in a ii7 chord, you should double the 3rd – just like in triads. The reason for this is that the third in a ii7 chord is the 4th scale degree, so doubling the third will give the chord a stronger subdominant sound. 

Remember to always resolve the chordal seventh down! In a ii7 chord, the chordal seventh will be the tonic. At first, you might think: why should I resolve the tonic down to the leading tone – shouldn’t be the other way around? While it is true that you should resolve the leading tone up, resolving the tonic down in this case is helpful when moving from a ii7 to a V or a V7 chord, since the leading tone is the 3rd in a dominant chord. Then, the leading tone will resolve back up when the dominant resolves to the tonic. This leaves beautiful stepwise motion in that voice 🙂

The one exception to resolving the chordal seventh down is when we write cadential 6/4 chords, which we will cover in Unit 5.6! Here, we will retain the chordal seventh for one more chord before resolving it down.