Modes can be built off all seven pitches in the major scale. As stated earlier in the book, the C major scale is also known as the Ionian mode. This mode is built off the first scale degree in C major. Similarly, if you build a mode off the sixth scale degree in C major, you will get an Aeolian mode or A-natural minor scale.
If you build a scale off the second scale degree in C major, you will discover a versatile scale known as the D Dorian mode. The intervals in the Dorian mode are whole, half, whole, whole, whole, half, whole. In C major, this becomes D to E (whole), E to F (half), F to G (whole), G to A (whole), A to B (whole), B to C (half), and C to D (whole). This scale is written in FIGURE 5-9.
FIGURE 5-9: The Dorian Mode
Like pentatonics, the Dorian mode is very effective and easy to use. The Dorian scale is almost always used over minor chords built on the second scale degree. In the key of C, this would be a D minor chord. As you will learn in Chapter 6, a minor triad rooted on D includes the notes D, F, and A. These notes, particularly the minor third, help define the Dorian mode. Additionally, this mode contains a major sixth. The major sixth is a critical feature of the Dorian mode. When you piece it all together, you will see that a Dorian mode is really just a natural minor scale with a raised (major) sixth. In fact, the Dorian mode uses the same notes as the natural minor scale located a perfect fourth below or a perfect fifth above the mode's root. For example, the notes in an A minor scale (A, B, C, D, E, F, G) match those of a D Dorian mode (D, E, F, G, A, B, C). The only difference is the starting pitches.
The Dorian mode is not limited to minor ii (two) chords. It can be used on the blues too. In its simplest form, the blues uses major triads built on the first, fourth, and fifth scale degrees (see Chapter 9). The Dorian mode can be used to solo over these chords provided you're careful to avoid certain perfect fourth intervals.
For example, in the key of C major, the I chord is a C major. Its chord tones are C, E, and G. The D Dorian scale can be used to solo over this chord, but you should generally avoid the note F since its relationship with C is a perfect fourth. In this context, it's best to navigate around perfect fouth intervals. The IV chord is an F major chord. Its chord tones are F, A, and C. Again, the D Dorian scale can be used on this chord. Here, you can play a B natural since it is an augmented fourth not a perfect fourth. (Raised fourths will be discussed later in the chapter.) The V chord contains the chord tones G, B, and D. Here, you may use the D Dorian mode, but you should avoid playing a C since it forms a perfect fourth with the root. The Dorian mode is paired up with the I, IV, and V chords in FIGURE 5-10.
FIGURE 5-10: Dorian Mode over I, IV, and V Chords
Once you add blue notes and/or other altered tones to the I, IV, and V chords, the Dorian scale becomes less handy. In other words, too many “avoid” notes crop up to warrant its use. Thankfully, there are other modes available, namely, the Mixolydian mode, the dominant scale, and the Lydian dominant mode. As you will see, all these scales have great blues applications.
As for other Dorian applications, use it freely on minor key modal jams. See “The Doors” section of Chapter 14 for an example. The Dorian mode gets a lot of use by artists who structure songs around a single minor chord or a series of minor chords. Miles Davis's “So What” is the perfect example. This tune contains only two minor chords: Dmin7 and E-flat min7. Progressions like these are fertile ground for Dorian modal explorations.