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.