I was recently asked to accompany a fiddler using modal keys. “Interesting”, I thought. What exactly did he mean by that? So I asked. His response follows.
• I refer to “modal”
[A modal] when I’m looking for no V-chords — instead, the flat-VII chord would be the typical second chord [ie: in the key of A, the second chord will always be a G, not an E]. These will hardly EVER have the 3rd of the chord present in the backup; just use open chords, or, in the case of DADGAD, use flavoring pitches such as the 9th, 4th, flat-6, etc. This type of backing is great with pipe tunes of the “Scottish gapped-scale” variety, the melodies of which skip the 3rds altogether [ie: Pipe Major Jim Christie of Wick March
*some gapped-scale tunes such as Lexi McAskill, which would normally be considered in A modal, can actually be played in Em modal with an electrifying effect.
• I refer to “minor modal” [Bm modal] when it’s clear that the melody has a flattened-3rd [ie: Congress Reel and Sean Ryan’s Jig use a C naturals]. This doesn’t necessarily mean that I like the backup chords to contain 3rds; I still prefer 3rd-free chords in most cases. The reason I indicate these differences in my charts is so that you know what’s happening in the melody.
• I refer to “mixolydian” [A mix] when it’s clear the melody has a major-3rd. These often sound fine backed up by chords with a major-3rd. But still, use 3rds very sparingly. As a melody player, I like to be able to create the effect of changing from major-to-minor or minor-to-major by changing the tune I’m playing, rather than having the guitarist give the effect away with the chords.
As for Dorian, I think of this mode as more relevant to describing the melodic content rather than the specific chord voicing.
The progression I to flat-VII , as you well know, is the tried-and-true standard for modal tunes. The use of the flat-VI chord [ie: F in the key of Am modal] is fantastic — exactly once. It’s a very powerful effect used near the end of a tune, but if it gets over-used the effect becomes trite.
An example of this is Track 12 of my ******* album, in which ***** used the flat-VI too many times successively and it got boring.
All of the tunes in the Laridee set are minor, and also modal. (That’s not to say that they can’t be re-tooled for cool effects.) The B-parts of several of the tunes go into the sub dominant IV area. [ie: the fourth tune uses Dm modal for the A-part and Bb chords for the B-part.]