Modal Progressions and Related Modes
Question by Richard
(Berwyn, PA USA)
Your lesson on minor modal progressions was done well and I get it, but to be clear, if I'm playing over a G major key with a G mixolydian, does the progression go to A aeolian, B locrian, etc.
Your question implies you understand the relationship between the modes (i.e. A Aeolian and B Locrian are, at least theoretically, relative to G Mixolydian).
However, if you're playing a Mixolydian progression, the progression
will not necessarily go to Aeolian or Locrian. If it did, then we would consider the progression to have "changed mode".
To change mode, the progression would need to stop resolving around Mixolydian's related chord and start resolving around another mode's chord.
For example, take this typical Mixolydian progression in G...
Gmaj / Dm / Am / Gmaj
Even though D minor's related mode would be Dorian and A minor's related mode would be Aeolian, we would still consider the entire progression to be Mixolydian because that is the chord on which the progression resolves. G Mixolydian, therefore can be considered the "tonic mode" or the tonal centre of the progression.
In other words, yes, see the related modes of Aeolian, Dorian, Locrian etc. for each chord if it helps you understand what you're playing, but also know that you're not necessarily changing mode
with each chord change.
For example, with the above progression, we'd just say it's in G Mixolydian. We wouldn't say it moves from G Mixolydian to D Dorian to A Aeolian.
I hope that's clear and helpful.