AEOLIAN: The Andalusian Sound and Relative Minor
The relative minor mode that leads into rock and roll and the Andalusian cadence.
WHAT IS AEOLIAN?
Aeolian is one of my favorite modes and is one those modes that has many names. I've seen it called the Relative Minor, Natural Minor, the Minor Scale, and just plain “Minor”. Some of these terms mean that we treat Aeolian as our parent scale and all other modes are derived from Aeolian. While Aeolian is from the Major Scale and is Ionian’s direct relative minor, so we can use Aeolian in conjunction with Ionian very easily. A quick Google search of the Circle of Fifths will give you all the key notes in fifths, which is where Ionian starts. Next to those notes are lower case letters denoting the Relative Minor or Aeolian.
Functional Harmony In A Minor Key
Minor keys like Aeolian can be tricky to navigate since most music lessons revolve around the Major Scale. To tackle this, we’ll look at functional harmony so that we can focus on just two notes to help us find our way.
The best way to think of functional harmony is by using the 4th and 7th degrees of a scale or mode to place chords into three groups: Tonic, Pre-Dominant, and Dominant. Chord progressions tend to move towards a Tonic. On the way we have Pre-Dominant chords that lead easily to Dominant chords, which in turn lead back to a Tonic. The way we group these chords is that Tonic chords do not use the 4th degree note, Pre-Dominant use the 4th degree and not the 7th degree, and Dominant chords use both the 4th and 7th degree notes. Some scales like Aeolian have a b7. We still consider this to be the 7th degree of our scale. It is simply flattened. Below is how this works with A Aeolian.
Dominance Through TriTones
Thankfully, music theory has a lot of overlapping concepts that let us bend the rules. The reason why we go to the 4th and 7th degrees is because the perfect fourth and major seventh degrees are a TriTone apart. Another way of saying this is that the natural 4th and natural 7th degrees are three whole steps apart. In A Aeolian these notes are B and F because you can go three whole steps from B to F, and then three more whole steps from F to the next B note.
Since this TriTone interval is the framework for building a Dominant chord, we can consider four other chord structures to also be Dominant in A Aeolian. The first is Bm7b5. The notes B and F are present, so we can easily use that to lead back to a Tonic of Am. The other three chord structures that have this are not so obvious.
FMaj7 comes from the Lydian mode in this context. Since F Lydian’s #4th degree note is B, we can treat Lydian chords like Fsus#4, FMaj7b5, and Fmaj7(#11) as Dominant chords and lead back to Am.
Dm comes from the Dorian mode and is the only minor mode with a natural 6th degree. Dm uses the notes D, F, and A. If we raise the 5th degree Dorian note of A to B then we get Dm6, which has a TriTone in it.
CMaj7 comes from the Ionian mode, but when Am is the Tonic we treat the note C more like a Chromatic Mediant with a Tonic function. To pull away from this “mediant” style of usage, we can use the notes B and F to lead back to Am. A chord like CMaj7sus4 has these notes.
In this way we can modify both of our Pre-Dominant chords and two Tonic chords to function as Dominant chords. Having such a wide variety of ways to resolve back to Am allows us to move in ways that keep things interesting for our listeners and us. Below is an updated chart that includes these alternate dominant functions.
Pre-Dominance Through Pivoting On The Fourth Degree
We can extend this way of thinking and use A Aeolian’s 4th degree note of D while avoiding both the note G and the TriTone interval created when we use both B and F. Starting with our bIII chord, a simple Csus2 comes close to achieving this with C, D, G. The problem is that the notes D and G are present, so this would have a Dominant function, which I’ll add in the next updated chart. To give our bIII chord a proper Pre-Dominant function we can use C6sus2, which uses the notes C, D, and A. A “major 6” chord can be though of as a minor chord with a major interval in the bass. It sounds major but feels like minor. In the context of A Aeolian, C6sus2 lets us use this feeling before moving on to any Dominant functioning structure.
Next up is Em7. This is a Dominant chord, but by suspending the note G up to A we can eliminate the Dominant function and reduce this to a Pre-Dominant function by retaining the note D. Em7sus or Em7su4 is E, A, B, D. Since this is just a suspension of Em7, we can play Em7sus4 as a Pre-Dominant chord and then Em7 as a Dominant chord that then leads back to our Tonic of Am.
Our bVI chord is a Tonic chord. To take this function and mode it into a Pre-Dominant state all we need to do is use another major 6 style chord like F6 or FMaj13. F6 is F, A, D and gives the same sense of a major with a minor feel. FMaj13 is simply an FMaj7 with the fifth degree note of C raised to D. Both chords use D and F, but avoid the notes B and G so there is no Dominant pull in either of them when progressing towards Am.
Adding Secondary Dominance
This whole time we have been moving towards Am. A great way to resolve to any note or chord is through a “Dominant 7” that is a perfect fifth above the target note. A’s perfect fifth note is E, but Em exists here. If we borrow E7 we have a chord that is not diatonic, or belonging to, A Aeolian. We can still borrow this chord and use the notes E, G#, B, and D to resolve to Am because all we really need in our target chord is the root and a perfect fifth. In this case those notes are just A and E.
Utilizing Harmonic Minor
The only thing that makes the chord E7 non-diatonic is the note G#. We can continue to use this one non-diatonic note and turn A Aeolian into A Harmonic Minor by simply raising our b7 degree to the major 7th degree. In other words, Aeolian uses degrees 1, 2, b3, 4, 5 b6, and b7 while Harmonic Minor uses degrees 1, 2, b3, 4, 5 b6, and 7. This may not seem like much of a change, but little changes can have huge consequences. If we use A Harmonic Minor for a moment while sticking to A Aeolian as our Tonic structure, then we can include the chord AmMa7 as a Tonic chord. This chord uses the notes A, C, E, and G#. Playing AmMaj7 and then Am can draw out the sound of A Harmonic Minor and then settle back into the sound of A Aeolian.
Another option is that we can play E Mixolydian b2b6 over the E7 chord. E Mixolydian b2b6 uses the notes E, F, G#, A, B, C, and D. These are the same notes as A Harmonic Minor, so E Mixolydian b2b6 is a mode of that scale. We can make sense of the extended use of this scale by playing E7 with Mixolydian b2b6 to AmMaj7 from A Harmonic Minor as all the notes are the same in both modes. Then we can flatten the note G# back to G and return to A Aeolian.
Using Aeolian’s Leading Tone
A Aeolian does not have a Leading Tone. Instead, G is the Sub-Tonic. To get a Leading Tone we will need to continue to use G# so that it can lead a half-step up to A. In the context of the Major Scale, the leading tone is a Half-Diminished structure. Since we are leading up to a minor we can use a Fully Diminished structure like G#°7. The °7 means to diminish the b7 from a Half-Diminished chord, which makes it a bb7 or double-flat seven. G#°7 uses the notes G#, B, D, and F. Think of it like a B diminished triad over a bass note of G#.
The Andalusian Cadence’s Secondary Tonic
It can be difficult to talk about Aeolian without mentioning the Andalusian Cadence. This is simply i, bVII, bVI, V7 to I, or Am, G, F, E7 to Am. Using the Secondary Dominant chord of E7 is what gives this flamenco style progression its flavor. There are many ways to use this four-chord progression, but if we listen to it, we get a sense of E acting as our Tonic as all of the movement flows toward it. Only when we declare that we are using E7 as a Dominant to Am do we feel A as the Tonic once again.
To better illustrate this concept, think of E as a temporary or secondary tonic. The Leading Tone of any Tonic is a half-step below, so E’s Leading Tone is D#. If we play an Andalusian style cadence like Am, G, F, D#°7, E7, Am then we get can feel E as the tonic note before using E7’s dominance to drive back to A as the tonic. We can also fit in G# using two of the previously mentioned chords and play Am, G, F, D#°7, E7, G#°7, AmMaj7, Am. The way this works is by playing Am, G, and F to start out an Aeolian progression. Next, we use D#°7 off the Leading Tone of E, which in turn becomes E7. E7 uses G# to help lead towards A, so we use G#°7 to lead to AmMaj7 from A Harmonic Minor, which also uses the note G#. Finally, we resolve to our Am triad which is part of both A Harmonic Minor and A Aeolian so that we can feel like either scale/mode is appropriate.
Using An Augmented Walk-Down
An enharmonic note is a note that shares the same pitch, so G# and Ab have this relationship. If we allow ourselves to bend the rules a little more, then we can use Am and flatten the first degree as we move down to G or G7. Doing so gives us access to the augmented chord Ab+, which uses the notes Ab, C, and E. The walk-down of root notes from Am to Ab+ and then G gives this a nice tense way of drawing our focus to G. The reason for this is because an augmented chord only has major third intervals or intervals of two whole steps. Like the Fully Diminished chord that only uses minor third intervals, the augment chord leads us somewhere. In this example the root note of Ab is a passing tone from A down to G, so Ab+ is a passing structure that fits between Am and G. You can do this walk down from any minor chord and down a whole step to a major chord as well as going from a major chord up a whole step to a minor chord, which would be considered a “walk-up.”
The Magic Key Change
This next part can be a bit of wild concept, so allow me to start by stating that any Fully Diminished chord can lead to any key that is not used as a note in such a chord. Whew!
Looking at G#°7 we have the notes G#, B, D, and F. If we play this chord to lead to a Tonic, then we can make any key that uses another note the new tonic. This key can be major or minor, so it can be either Ionian or Aeolian. This is due to the way a Fully Diminished chord is equal to all its inversions. G#°7 = F°7 = D°7 = B°7. This causes all the notes to behave as root notes.
Using the circle of fifths shown above, all the major keys (Ionian) are on the outside of the circle and all the minor keys (Aeolian) are on the inside of the circle. The G#°7 uses notes that are “balanced” across the circle to create a square or diamond shape in the diagram. The importance of this shape is that the four notes of G#°7 overlap in both the major and minor keys. To resolve this chord, we simply need to move to a major or minor (Ionian or Aeolian) that is rooted in a note that is not part of the diamond shape. A, A#/Bb, C, C#/Db, D#/Eb, E, F#/Gb, and G can all be used as the Ionian or Aeolian Tonic of a new key. With eight options you might think that this is a bit much, so let’s use one new key to see how powerful this is.
Instead of going from G#°7 to Am, I’ll take G#°7 to Cm. I now have the notes C, D, Eb, F, G, Ab, and Bb along with the chords Cm7, Dm7b5, EbMaj7, Fm7, Gm7, AbMaj7, and Bb7. I can use the same roman numerals as before and call them i, ii°, bIII, iv, v, bVI, and bVII. While all I did was change keys/notes, I can now play C Aeolian and use chord progression that I excluded when playing A Aeolian. If I used the Andalusian Cadence in A Aeolian, then I’ll avoid that in C Aeolian to give my song a new feel. When I’m ready to lead C Aeolian I can play G#°7 or any of its inversions and return to A Aeolian. A quick example of this would be to use A Aeolian and the Andalusian Cadence with Am, G, F, E7 and then G#°7 to go to C Aeolian with Cm, Ab, Bb7, Gm, which I can then return to A Aeolian with D#°7 to Am.
|Am |G |F |E7 G#°7|
|Cm |Ab |Bb7 |Gm |
|D#°7 |D#°7 |D#°7 |D#°7 |
|Am |
Twoing The Five
“Twoing the Five” is a Jazz concept that uses a minor 7 chord a fifth above a Dominant 7 chord before resolving or progressing on. In A Aeolian we have G7 as our diatonic Dominant 7 chord. G’s perfect fifth note is D, so Dm7 to G7 to Tonic is a great way to “Two the Five”. This is notated as ii7/V7 and in the context of Aeolian could also be viewed as ii7/V/i. All of these chords are diatonic to A Aeolian, so what do we do with E7? We do the same thing. E’s perfect fifth is B, so we can also play Bm7 to E7 to Am. This would be notated as ii7/V7/i. The difference here is that the V7 implies that we are using Am’s V7 of E7, where in the previous example we used Am’s V chord that happened to be a Dominant 7.
We can take Twoing the Five farther by playing a progression like Am, G, F#m, B7, Bm7, E7, Am. In this example we use F#m as the ii7 of B7. B7 is then transformed into the ii7 of E7, which then resolves to Am. Twoing the Five can add some brightness to your minor songs that work great due to the chords progressing in fifths, which in this example F# is the fifth of B, which is the fifth of E, which then the fifth of A.
The Phrygian Flat 2 In Aeolian
So far we’ve used every note as a root note for a chord except Bb. To not be outdone by this one note I’ll use BbMaj7. This comes from the parallel mode of A Phrygian, which is the same as A Aeolian, but with a flattened second degree. This mode has a Lydian Maj7 chord built off the b2 degree. To make this work I like to play Am, BbMaj7 (notes are Bb, D, F, and A) and then back to my Am, G, F, E7 progression. This momentary movement out of A Aeolian let’s me move into the key of F and then back again. It also lets me add some interest a grab the listener’s attention if I feel that my song is becoming too repetitive. Because the BbMaj7 has the note D in it, we can treat it as a Pre-Dominant chord borrowed from the key of F.
A Big Recap
Because we’ve done so much with Aeolian, I though I’d put everything discussed here into one big chart. This can be confusing if you’re new to music, so I will also post some videos on how to use some of these ideas to enhance your usage of Aeolian that I’ve included here. Please check out my Instagram page at https://www.instagram.com/musictheoryforeveryone/
