A Player's Guide to Chords and Harmony (29 page)

Figure 7-14. Above a major 7th chord, such as the E6maj7 in measure 2, you can use notes from the Ionian mode.

Figure 7-15. Some chord changes require that the mode used for the melody change drastically from measure to measure. Here, F Dorian in measure 1 is followed by E Mixolydian in measure 2.

If you've looked closely at Figures 7-14 and 7-15, you may be wondering why in both of them I skipped the 4th scale step of the Ionian mode over the major 7th chord. Depending on the harmonic context, this note may not sound very good, so it's sometimes skipped. Some other modes have notes that can clash with the underlying harmony: Musicians often skip the 4th step when playing in the Mixolydian mode and the 6th step when playing in the Dorian mode. Figure 7-16 shows these modes as they might be employed by a soloist. Other alterations in the modes are possible; we'll look at a few of them later in this chapter.

Figure 7-16. When drawing melody notes from a mode, it's not necessary to use all of the notes of the mode. The 6th step is often skipped in Dorian mode, and the 4th step is often skipped in Mixolydian and Ionian.

Speaking of scale notes that don't sound good, I've noticed that many guitarists have a bad habit of using the Dorian mode when soloing in a minor key - that is, the Dorian whose root is the tonic of the key - even when the chords they're soloing over include a minor IV or a major triad on the 6VI. Since the Dorian has a raised 6th step (Aq in the key of C), while these two triads use a lowered 6th step (A6 in the key of C), Aeolian mode might be a better choice. Some guitarists may employ this harmonic clash deliberately to heighten tension, but I'm fairly sure a lot of them do it because they're not paying enough attention to which modes fit with which chords.

The Lydian, Phrygian, and Locrian modes are used less frequently in pop and jazz music, but they're worth knowing about. The Locrian mode can be used over a m765 chord, as shown in Figure 7-17. Lydian is used over a major9#1 1, as shown in Figure 7-18, or over a IVmaj7 Phrygian is seldom used in its unaltered form, because the flat 2nd and 3rd steps give it a somewhat foreign sound. Aeolian may or may not be used for soloing and melodies, depending on how you look at it: If the 6th step of the mode is left out, as it would usually be, Aeolian is the same as Dorian (see Figure 7-16). Aeolian is important for another reason, however: It's better known as the natural minor scale.

Figure 7-17. Over the Em765 in measure 1, the right-hand line uses the E Locrian mode.

Figure 7-18. Over a major 7th chord with a sharp 11th, the Lydian mode works well.

MINOR SCALES

The concept of minor keys was introduced in Chapter Four. Each major key, you'll recall, has a relative minor key. The relative minor has the same key signature as its relative major, and its tonic is a minor 3rd below the tonic of the major. If you surmise from this description and from Figure 7-10 that the basic scale of a minor key is the Aeolian mode, you'd be right. Figure 7-19 shows the relationship. C major is the relative major of A minor (and A minor is the relative minor of C major). The Aeolian mode whose tonic is A has the same notes as the Ionian mode whose tonic is C.

As was explained briefly in Chapter Four, however, the V triad in a minor key is sometimes altered from minor to major in order to provide a more satisfying harmonic movement. When this triad is altered, its 3rd, which is the 7th step of the minor scale, is raised. In addition, the 6th step of the scale is sometimes raised. As a result, the minor scale has some significant variations that the major scale lacks.

The Aeolian mode is called the natural minor scale, because neither its 6th nor its 7th step is altered. (This term has nothing to do with whether the 6th and 7th steps are spelled with naturals or flats. It simply indicates that the scale is in its natural, unaltered state.) When the major V triad or dominant V7 chord is used, the 7th note of the scale (the 3rd of the V chord) is raised by a half-step. This scale, which is shown in Figure 7-20, is called the harmonic minor scale, because the leading tone has been raised to coincide with the harmony (the major V triad). The harmonic minor scale sounds faintly odd or exotic to our ears, because it contains an augmented 2nd interval. In fact, it sounds odd enough that composers often prefer to avoid it. They do this by raising the 6th step of the scale whenever it's being used before a raised 7th.

Figure 7-19. The key of A minor is the relative minor of C major, and C major is the relative major of C minor. An interval of a minor 3rd separates the roots of any relative major and its relative minor. The relative minor uses the Aeolian mode as its scale.

Figure 7-20. The harmonic minor scale contains an augmented 2nd interval (from F to G# in the A harmonic minor scale).

In classical music of the 18th and 19th centuries, the norm was to write melodies in such a way that both the 6th and 7th steps of the minor scale were raised - but only when the melody was moving upward. The raised leading tone would be preceded by a raised 6th step: As a result, the upper half of the minor scale would be the same as the upper half of a major scale. Only the lowered 3rd step would indicate that the scale was minor. When the melody was moving downward, however, the natural minor scale would most often be used instead. This practice, which is illustrated in Figure 7-21, is not followed in any rigorous way by modern composers, but it gave rise to the terminology used to describe these scales. A minor scale in which both the 6th and 7th steps have been raised is called the ascending melodic minor scale. Sorry, sports fans - it's a bloated, clumsy term, but we're stuck with it. The descending melodic minor scale is the same as the natural minor scale, so the term "descending melodic minor" is used less often.

The ascending melodic minor turns out to be an interesting scale in its own right. As shown in Figure 7-22, it has a different pattern of whole-steps and halfsteps than any of the modes discussed above. Compare Figure 7-21 to Figure 7-11: None of the modes in Figure 7-11 has four whole-steps in a row. Their whole-steps are all in a 3/2 pattern.

Figure 7-21. The melodic minor scale has two forms. When the line is moving upward, the 6th and 7th steps are raised, but when the line is moving downward, they're not raised.