In Western music, there are two basic tonalities: major and minor. There are scales that correspond to the tonic of a major and minor key, respectively, the major scale (also called the Ionian mode) and the natural minor scale (also known as the Aeolian mode). When we refer to any of the modes derived from the major and natural minor scales, we (somewhat confusingly) say they come from major harmony. That means that we can extract all the modes simply by starting them on the various notes of the scale. For example, the natural minor scale has the same notes as the major scale, only it starts on the major scale’s 6th note.
I like to think of the other modes in major harmony as being put into major- and minor-sounding groups, as defined by whether the scale contains a major 3rd or minor 3rd. Look at the two bars in each line of Examples 1 and 2. I use the major (Ex. 1) and minor (Ex. 2) as the foundation and then show how other modes compare. Learn and understand them. The Ionian mode is the major scale, the Lydian is major with a #4th degree, and the Mixolydian is major with a b7. The Aeolian mode is the natural minor scale, Dorian is minor with a n6, Phrygian is minor with a b2, and Locrian is minor with a b2 and a b5. As listed here, these could be described as parallel modes—all have the same root but are derived from different keys.
The last bar of each pair shows chord arpeggios derived from each mode, including the tensions. The tensions are notes other than 1, 3, 5, and 7 (the chord tones) that are derived from the mode associated with each chord. They are built by stacking diatonic 3rd intervals based on the notes available in the scale. In other words, the chords have all the notes of the associated mode; they’re just ordered in 3rds instead of consecutively. We use the intervals 9, 11, and 13 because the tensions are typically played an octave above where they reside within the scale. To determine the interval from the tonic that each tension refers to, simply subtract seven.
Next time we’ll explore modes and chords derived from minor harmony, especially from the melodic and harmonic minor scales. As you study the above, I want to emphasize that these are not rules. They are building blocks—guidelines to playing. As you grow, you’ll find many alterations, substitutions, and possibilities for the chord scales.
Ed is currently freelancing in the Boston area. He holds a MM in Jazz Studies from New England Conservatory and has served as assistant professor at Berklee College of Music and Bass Department Chair at Los Angeles Music Academy.