Modelos Educativos

The tonic/dominant relationship in music is so strong that composers sometimes use a dominant function-ing chord on ones other than the tonic, like on the ii chord, or perhaps even the V chord itself. We saw this earlier in the “Aura Lee” example with D⁷ leading to G⁷, and A⁷ leading to D⁷. These chords are called sec-ondary dominants. You will recognize them in chord progressions as a major chord when you are expecting a minor one, and especially a dominant seventh chord when you are expecting a simple triad.

As an example, let’s look at the C major progression: C-Am-Dm-G⁷. A common variation on this progres-sion is C-Am-D⁷-G⁷. We would normally expect a D minor chord rather than a D⁷ chord in C major. But if we think a little bit about this progression, we can see that the D⁷ chord is the dominant seventh of G!

Figure 3-06

Musicians can use secondary dominants on almost any chord in a key to provide some variety to a pro-gression, and to give some temporary focus to another chord. The D⁷ chord in the above progression has a different sound quality than a simple D minor chord, which is what is normally found here. In addition, because the chord has a dominant function, it draws attention to the following G⁷ chord. It’s as if the chord progression has temporarily changed keys to G, but more on that topic later!

As I just mentioned, you can lead to almost any chord with its own dominant. This chord will be a major chord or dominant seventh chord a fifth away. Building on the last example, you could lead to D with A⁷, which is five steps away from D, the interval of a fifth.

Figure 3-07

We can keep going! The fifth of A is E. An E⁷ chord can lead to any type of A chord. Earlier we saw E⁷ lead to Am in “Aura Lee.” Here now is an example of E⁷ leading to A⁷. Figure 3-08 shows a series of dominant seventh chords that begin on E⁷ and move to C.

Figure 3-08

Another common secondary dominant progression is I⁷-IV. In C major, this progression is C⁷ moving to F. An example of this secondary dominant’s use is in the larger progression F-G-C-C⁷-F-G-C. The pro-gression is in C major, but the C⁷ chord is functioning as a dominant seventh of the F chord.

Figure 3-09

The most common secondary dominants are the ones we have looked at here, those that lead to I, ii, IV, V, and vi. Musicians generally do not use sec-ondary dominants that lead to vii^b5. V⁷ of iii is pos-sible, but it is not that common.

You can see from the chord symbols, especially with the Roman numerals, that secondary dominants are an altered version of an existing chord. This change to the chord is to create a dominant seventh. What gives it its secondary dominant function is that it leads to another chord a fifth below. The I chord is altered to I⁷ to create movement towards IV. The ii chord is altered to II⁷ to highlight V, and so on.

Secondary dominants are like mini key changes.

Think of the chord progression in C major where G⁷ leads to C. This is a common V⁷-I progression in C major. But what if these two chords appear in F major, as in the progression: F-Dm-G⁷-C?

Although the progression as a whole is in F major (I-vi-II⁷-V), the G⁷ chord has notes in it that do not belong to this key, but rather its notes belong to C major. For your solos to work in this chord pro-gression, you would start out in F major, but when you get to the G⁷ chord, you would switch patterns to C major. Finally, when the C chord sounds, you need to switch back to F major patterns.

Let’s summarize the above. G⁷ is the dominant sev-enth chord of C major. When G⁷ appears in any key other than C and leads to a C chord, it is a secondary dominant. The same is true for any other functioning dominant seventh chord.

When playing over a secondary dominant you need to switch to its parent major scale. Let’s revisit the secondary dominants progressions we looked at earlier.

50

Figure 3-06 C-Am-D

-G

This progression is I-vi-II⁷-V⁷ in C major. The D⁷ chord belongs to the key of G. Use G major pat-terns over D⁷ and then return to C major on the G⁷ chord. When you play G major patterns over the D⁷ chord, you are actually playing in D Mixolydian, the dominant scale of G. By the way, switching scales like this is no easy task! Generally speaking, you will only hear solos played over progressions like this in jazz and country styles. mode, or an A dominant scale. Now you need to switch scales twice. Good luck!

Figure 3-08 C-E

-A

-D

-G

-C

I-III⁷-VI⁷-II⁷-V⁷-I in C. E⁷ belongs to A major, A⁷ belongs to D, and D⁷ belongs to the key of G. Think

“dominant scale” over each dominant seventh chord. That is, for each dominant seventh chord play its parent major scale. Of course, that’s if you are even playing at all. At this point you may have given up on trying to follow all these changes!

It can be quite challenging to switch scales over secondary dominants, but it is not always necessary. With the right note selection, you can stay in one scale and avoid any troublesome notes. We saw this in the “Aura Lee” example. Notice that the melody remains in the key of C even though secondary dominants appear in the progression. It even uses an F note over an A⁷ chord to good effect, a note that is not part of the A dominant scale.

Exploring the details of how guitarists play over secondary dominants is really beyond the scope of this book, but now at least, you should understand the basic idea. While approaching the progressions in this chapter as a lead guitarist may be challenging, playing the chord progressions themselves is not hard at all.

You will probably begin to recognize that secondary dominants are fairly common in popular music. With some careful listening, you will hear that players often do not even attempt to solo over them. What a relief!