Modes
The term "mode" is another name for a scale. There are seven different modes which can be derived from the major scale by starting on each of the seven notes of the major scale. These modes were first used in ancient Greece and have been widely used throughout history in all types of music. Each of these modes can be played in any key. Just as there are twelve major keys, there are also twelve possible starting notes for each of the modes. Any note of the chromatic scale can be used as a starting note for any mode. This requires a knowledge of the formula for each mode. The names of the seven modes derived from the major scale are listed below along with their scale degrees.
Mode Formula
Some of these modes are particularly useful for creating chord progressions which don’t sound like a typical major or minor key. The Ionian mode is the major scale, so you already know what its possibilities are. The aeolian mode is the natural minor scale, which has also been dealt with earlier in the book. After these, the most commonly used modes are the mixolydian and the dorian, followed by the phrygian, Iydian and lastly the locrian. The example below demonstrates a typical Mixolydian Rock riff. The three chords used here - G, D and A also occur in the key of D Major, but as you can hear, the tonality is clearly based around A rather than D. To learn more about modes in general, see Progressive Scales and Modes for Guitar, or Progressive Complete Teach Yourself Jazz Guitar Manual.
