I've been dabbling in music for years but don't have a lot of theory background. I'm trying to confirm a pattern I've seen in YouTube videos to see if I can reason out all the diatonic chords in a given key or mode.
For the sake of simplicity, I'm going to use the example of D Dorian so that I don't have to type a bunch of sharps and flats. If I want to know all the diatonic chords in D Dorian, is this a reasonable approach?
- Determine the D Dorian scale. That should be: D E F G A B C
- Build a list of chords based on the 1st, 3rd, and 5th for each of the chord tones. For D Dorian, this should result in:
- D F A (Dmin)
- E G B (Emin)
- F A C (Fmaj)
- G B D (Gmaj)
- A C E (Amin)
- B D F (Bdim)
- C E G (Cmaj)
If that is all correct, would it also be correct to determine all the diatonic 7th chords the same way? In other words, starting with the same D Dorian scale as before, build a list of seventh chords consisting of the 1st, 3rd, 5th and 7th notes, starting from each chord tone:
- D F A C (Dmin7)
- E G B D (Emin7)
- F A C E (Fmaj7)
- G B D F (G7)
- A C E G (Amin7)
- B D F A (Bdim7)
- C E G B (Cmaj7)
If everything so far is right, am I right in assuming I can build all the 9th, 11th, and 13th chords in exactly the same way by just adding the 9th, 11th, and 13th notes to the chords? (I'm not going to attempt that here because it's likely going to raise more questions as to what to name each chord; I'll save that for a followup question.)
If this is all right, then I'm kicking myself that I didn't see this years ago! This opens the door to putting the appropriate chords against a melody, which has always seemed very mysterious to me since I was never shown how to figure out the right chords to use.
I realize this is only a formula for figuring out diatonic chords and doesn't even touch the wondrous things you can probably do with chromaticism but I figure I should walk before I run :-)