A Dorian scale/chord progressions

Question

I'm currently jamming a song in G Major with focus on the A Minor. The chord progression goes Am C D. I know that the A Minor Blues Scale sounds pretty sleek, but I just have the feeling that A Dorian makes it a lot more interesting, which makes sense to me because I put the focus on the second chord of G Major which is A Minor.

Are there "compulsory" chord progressions in a Dorian Mode? Or can I just jam the Dorian scale over any progression that starts with the Dorian root and has chords the chords of the key? And theoretically I play a I IV V in A Dorian, which gives it this Bluesy/Funky feeling, a bit like Zappa.

Answer 1

There are no "compulsory" chords, but if the music is to sound Dorian, then you want to emphasize A and the total progression should have every note in the mode represented, so it could help to add a chord including 'b' in your progression, such as G Major, B minor or E minor. Depending upon how much you want to follow historical practice, a cadence involving E Major was often added.

Answer 2

I put the focus on the second chord of G Major which is A Minor

Not only is A minor the "second chord" (i.e., the ii chord) of G major, but A Dorian is the "second mode" of G major. That is, the A Dorian and G major scales have the same key signature. Put another way, A dorian and G major have exactly the same pitches in them.

Are there "compulsory" chord progressions in a Dorian Mode?

In order to make a mode sound "modal", one should simultaneously emphasize the unique pitches in that mode — the ones that differentiate it from other, similar modes — and deemphasize the similarities.

Dorian and (natural) minor are very similar, differing only by the sixth note in the scale:
A minor = A B C D E F G
A dorian = A B C D E F# G
More specifically, a scalar passage in minor might contain adjacent F# and G#, F and G, or F and G#, but not F# and G – the latter is unique to Dorian.

Thus, to create a "dorian" chord progression, it helps to emphasize the shift from F# to G or G to F#. VI VII i and III ii i will accomplish this while also clarifying the tonic pitch, which is also necessary to ground the mode. (For example, if you emphasize G instead of A, it's going to wind up sounding like G major.) The progression mentioned in the OP, Am C D, is i III IV in A dorian and also prominently employs the F# G shift.

While i IV v also includes the tonic and the 5-6 (F# G) point of emphasis, the progression overall is so characteristic of major and minor that should be used carefully, if not avoided.