What would be the key of this progression? I would say that its A minor being the progression then I – IV, but D7 should be a minor chord as Dmin or Dmin7. Thanks!
It could possibly be a number of things depending on context. However, this is most likely to be A dorian.
ii-IV is a very typical two chord vamp for Dorian.
If we break it down the first clue here would be the D7. There’s only one dominant chord in each key so we can quickly figure out that D7 is the V7 of G major.
Am7 is the ii chord in G major so now we know that the chords both belong to the key of G.
If the D was just a straight D major, we’d still come to the same conclusion, it might just take a little longer to work out.
We know that these two chords belong to G major but when we play the chords, it sounds more like Am is the home key so A dorian would make the most sense as it’s the ii chord in G major.
