More on Modes

Q: Great dorian lesson, thanks. But when we see a Dmin7 on a chart while jamming, and thinking whether we should play a pentatonic a mode or whatever, isn't that decision should be strictly related on the KEY of the song? Aren't we risking playing notes completely out of key when we use modes?

A: Great question. It's all about musical context. There are two kinds of harmony and for the lack of better words let's say that one is functional harmony and the other is non-fuctional, modal or maybe static harmony (for lack of better words). When we talk about functional, we are talking about chords that work together inside of a particular key. So a Dmin7 chord inside of a Cmaj7-Fmaj7-Dmin7-G7 progression is functioning as a "ii" chord. As you know the "ii" chord is the dorian chord. If you tried to play one of the other minor modal scales it would sound wrong. You don't even really want to be thinking modes in this case anyways, I mean it's just a C major progression and that's all you really to know or consider. We hear the tonal center of this progression as C major.

Modal harmony doesn't work this way. For something to be modal, the chords can't be functioning inside a diatonic key system (matter of fact you'll notice that most modal songs don't have key signatures), in the case of our Dmin7 chord, it has to be static. Some possible examples would be 16 bars of Dmin7 followed by 8 of an unrelated chord, like Ebmin7. I'm using the song "So What" by Miles Davis as an example. And the general weapon of choice for this song would be a D dorian scale followed by an Eb dorian scale. Dorian is the general mode of choice here but you could just as well use a phrygian scale or aolian scale for that matter, there are no other diatonic chords pulling the ear to a tonal center so it doesn't make any difference. The less chords the better and probably one chord is best. If you want to mix modes, the chords in your progression have to be unrelated, Like a Dmin7-F#min7-Bbmin7 progression. In this case you would want to play D dorian, F# dorian and Bb dorian scales. Another thing to remember is that the bigger the chord, the less choices you have. In other words, over a Dmin7 chord, you have D dorian, D phrygian and D aolian as possible choices. If your chord was a Dmin9 chord, phrygian has to be excluded because the D phrygian scale doesn't have a E natural (the 9th) in it. If you turn the chord into a Dmin13 or Dmin6 chord, the only choice you have is a D dorian scale because it is the only scale that has a 6th in it. You want to look at scales from this perspective: Dorian: 1-2-b3-4-5-6-b7, Phrygian: 1-b2-b3-4-5-b6-b7, Aolian: 1-2-b3-4-5-b6-b7. By looking at scales this way, you can see what chord go with what scales.