Modes and chord scales

Modes can be used in a couple of different ways. Either as the tonal center for a song or section of a song, or as a scale that can be used over a specific chord.

You can build a chord from each degree of the major scale, and you can build a mode from each degree of the major scale. Therefore each chord will have a corresponding mode associated with it.

Below is a chart of the 7 modes and the basic triads and 7th chords associated with them.

Now I know that you are thinking.......if all of these modes contain the same notes, why would I want to think of a different scale for every chord?

Say you have this chord progression that you are going to improvise over.

C Am Dm G

You could look at this chord progression, see that all of the chords come from a C major scale, and just improvise with that scale. That is key area thinking. All of those chords are in one key, so you would just blanket all of them with one scale. The advantage of this type of thinking is that it doesn't require much thought. You can instinctively search for melodies in that scale. The disadvantage is that you are not considering how the notes in the scale sound in relationship to each individual chord.

Another way that you could think about improvising over this chord progression is to think about how the notes in the C major scale relate to the notes of each chord.

Below are the 4 modes for the C Am Dm G chord progression.