This year I've been attending a jazz workshop. A lot of the material is familiar to me, but I haven't been playing much jazz in the past few years. The topic of the modes came up, a topic that I find fascinating. I'm explaining this more or less to myself, so that I can get a better grasp of it.
The modes were developed in Western medieval music theory, more or less forgotten after the baroque period, and revived in late nineteenth century classical music and in jazz, as a way of conceptualizing what we play.
Essentially, the modes are very simple. They are all based on the ordinary diatonic scale, as in C major: C-D-E-F-G-A-B-C. This is the model for all major scales: base note (C) -major second up (D) - major second up (E) - minor second up (F) - major second up (G) - major second up (A) - major second up (B) - minor second back up to the base note an octave up (C).
In the major scale, which is also called the Ionian mode (the Greek names for the modes are entirely artificial, but that's what they are), the first five notes (CDEFG) have the same structure as the five notes ascending from the fifth (GABCD). The strong notes in the scale are the first, the fifth, and the fourth. The fifth, known as the dominant, gravitates toward the first, the tonic, and the fourth, the sub-dominant, can gravitate toward the fifth. When people improvise in jazz in the Ionic mode, they tend to avoid the fourth.
In Western harmonic theory, every major scale has a relative minor, the natural minor, which begins on the sixth degree of the scale. In C major it is: A-B-C-D-E-F-G-A (the two variants, the harmonic and melodic minor, which I'll ignore for the moment). The natural minor scale is also known as the Aeolian mode.
There are two ways of thinking about the other modes. The easy way is to remain with the white notes on the piano and conceptualize the modes as beginning on various degrees of the C major scale. Thus, the Dorian mode, another minor scale, begins on the second degree of the scale: D-E-F-G-A-B-C-D. When I improvise in the Dorian mode (in fact, in all the modes) I find it difficult not to gravitate toward what would be the tonic (C) in the major scale that it's based on. This creates an inherent tension in the use of this scale. In jazz harmony (to jump ahead a bit), the Dorian mode is related to the II chord, in the basic chord progression of II-V-I.
The third mode is the Phrygian, and it begins on the third degree of the scale (E-F-G-A-B-C-D-E). This is a common mode in a lot of folk music, but the minor second between E and F sounds very odd to Western ears, so it's an interesting mode.
The next mode is the Lydian mode, starting on the fourth degree of the scale: F-G-A-B-C-D-E-F. It's a lot like the F major scale, but the fourth degree, the B, which would be a Bb in F major, is raised. The Lydian mode sounds strange and wrong to me when I improvise in it.
The mode that starts on the fifth degree of the scale is the Mixolydian, a major scale with the seventh degree flatted (G-A-B-C-D-E-F natural -G), as in the dominant seventh chord, which resolves to the tonic (G7-C).
I've already mentioned the Aeolian mode. The final mode, called the Locrian, is the weirdest mode, because it begins with a minor second (B-C) and the fifth is flatted (F natural): B-C-D-E-F-G-A-B. In jazz harmony it is associated with the half-diminished chord (B-D-F-A) and resolves to the tonic.
The modes were developed in Western medieval music theory, more or less forgotten after the baroque period, and revived in late nineteenth century classical music and in jazz, as a way of conceptualizing what we play.
Essentially, the modes are very simple. They are all based on the ordinary diatonic scale, as in C major: C-D-E-F-G-A-B-C. This is the model for all major scales: base note (C) -major second up (D) - major second up (E) - minor second up (F) - major second up (G) - major second up (A) - major second up (B) - minor second back up to the base note an octave up (C).
In the major scale, which is also called the Ionian mode (the Greek names for the modes are entirely artificial, but that's what they are), the first five notes (CDEFG) have the same structure as the five notes ascending from the fifth (GABCD). The strong notes in the scale are the first, the fifth, and the fourth. The fifth, known as the dominant, gravitates toward the first, the tonic, and the fourth, the sub-dominant, can gravitate toward the fifth. When people improvise in jazz in the Ionic mode, they tend to avoid the fourth.
In Western harmonic theory, every major scale has a relative minor, the natural minor, which begins on the sixth degree of the scale. In C major it is: A-B-C-D-E-F-G-A (the two variants, the harmonic and melodic minor, which I'll ignore for the moment). The natural minor scale is also known as the Aeolian mode.
There are two ways of thinking about the other modes. The easy way is to remain with the white notes on the piano and conceptualize the modes as beginning on various degrees of the C major scale. Thus, the Dorian mode, another minor scale, begins on the second degree of the scale: D-E-F-G-A-B-C-D. When I improvise in the Dorian mode (in fact, in all the modes) I find it difficult not to gravitate toward what would be the tonic (C) in the major scale that it's based on. This creates an inherent tension in the use of this scale. In jazz harmony (to jump ahead a bit), the Dorian mode is related to the II chord, in the basic chord progression of II-V-I.
The third mode is the Phrygian, and it begins on the third degree of the scale (E-F-G-A-B-C-D-E). This is a common mode in a lot of folk music, but the minor second between E and F sounds very odd to Western ears, so it's an interesting mode.
The next mode is the Lydian mode, starting on the fourth degree of the scale: F-G-A-B-C-D-E-F. It's a lot like the F major scale, but the fourth degree, the B, which would be a Bb in F major, is raised. The Lydian mode sounds strange and wrong to me when I improvise in it.
The mode that starts on the fifth degree of the scale is the Mixolydian, a major scale with the seventh degree flatted (G-A-B-C-D-E-F natural -G), as in the dominant seventh chord, which resolves to the tonic (G7-C).
I've already mentioned the Aeolian mode. The final mode, called the Locrian, is the weirdest mode, because it begins with a minor second (B-C) and the fifth is flatted (F natural): B-C-D-E-F-G-A-B. In jazz harmony it is associated with the half-diminished chord (B-D-F-A) and resolves to the tonic.
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