If you’re in a composition rut, have you tried writing a song in the Mixolydian mode? You retain the major qualities of an Ionian song, but with a different twist: the lowered seventh. If you haven’t read my previous entry on the mixolydian mode, you can find it right here. There’s a couple of angles you can go, so read on!
Background:
Let’s harmonize the mixolydian mode in both the keys of G and C. If you play a fretted instrument (like the guitar), the rules of transposition apply. If you decide that a song sounds better on A Mixolydian vs. G Mixolydian (low G on the third fret), simply move all the chords two frets higher. If you play an instrument like the piano, simply play the major scale, except lower the 7th interval by one half step.
- G Mixolydian: G 7th – A min7th – B dim or (B min7thFlat5th) – C maj7th – D min7th – E min7th – F maj7th – G 7th
- C Mixolydian: C 7th – D min7th – E dim or (E min7thFlat5th) – F maj7th – G min7th – A min7th – Bb maj7th – C 7th
Following a pattern of:
- I 7th – ii min7th – iii dim or (iii min7thFlat5th) – IV maj7th – v min7th – vi min 7th – VII maj7th – I 7th
Application:
So the first thing we notice is that the first chord is is a dominant chord. In standard or traditional applications, the dominant chord precedes the resolution chord in what we know as a standard or authentic resolution. By that rational, the first chord naturally wants to “go” to it’s fourth chord, which naturally has the I-V7 relationship in the Ionian mode. So it’s only fitting that the I7 to IV maj7th would be a strong progression in the mixolydian mode. Try it:
- G7 to C maj7 or
- C7 to F maj7
Try it various forms, ie: a C to F progression will resemble the I – IV part of the progression in a blues pattern. It also resembles a plagal cadence found in hymns. Although this is a strong progression, it’s nothing too new under the sun. This progression does not differntiate itself from an Ionian I-IV. However, a I7-IV, I7-IV maj7th mildly interesting, since you have a chord progression starting in a dominant chord progressing to a major 7th IVth.
The next application is the relationship between the I7 to v min7th. This is super interesting for a couple of reasons. One, with respect to the ionian mode, the mixolydian mode does not retain such a strong resolution as the ionian’s V7 to I (called the authentic) resolution. In fact, with respect to the ionian mode and its resolution, this is called the half open resolution (where a ii resolves to a V7), which leads to the second point of interest.
Using the IVth, the ii (min7) can be effective. Instead of a ii-V-I, or a IV-V-I progression (from an inonian mode), how about we use the v-IV-I progression and/or resolution? Try it, it sounds kind of cool:
- G7 – D min – C
- C7 – G min – F
Not as interesting is the mixolydian’s ii-v-I7 resolution. In the ionian mode, you have the dominant in a ii-V7-I. So the mixolydian’s v-I7 resolution isn’t as strong, while the I-ii progression in both modes are the same. If you want to differentiate between the modes, you can add the 7th in the I (in the mixolydian, as oposed to the I maj7th for the ionian).
One thing cool is the relationship between the third chord and the six chord. The ionian’s relationship is iii-vi while the mixolydian’s is iii dim – vi. This could make for an interesting bridge. Diminished chords can act as a sub for a dominant (like B dim subing for G7 in the key of C, read it here, or the appendix notes below).
Last thing, try a vii dim – I (not I7) or a ii-vii dim-I progression. Sound familiar? It should, if you believe that the diminished chord can sub for a dominant, then it’s a ii-V7-I transposed to the mixolydian’s ii-vii dim-I.
References:
- http://koolaborate.wordpress.com/2009/07/23/on-the-mixolydian-mode/
- http://www.guitarnoise.com/lesson/chord-substitution/
Appendix A: Diminished Chord Substituion:
The easiest way to explain this is to look at two chords in the key of C major (or ionian). A G7 chord is GBDF. A B diminished chord is BDF. See the commonality? The most important notes in a G7 are B and D because they are the third and seventh degree, which determines the G’s major quality and its seventh quality. Both are present in the B diminished.