The Aeolian Mode is the sixth mode of the Diatonic Major Scale. Let's look and listen to it with a bit more detail.
The Aeolian mode is often described as the white keys on the keyboard from A-A'. This gives us the following intervallic series:
*w=whole step // h=half step*
And the notation looks like this:
That's the notes A B C D E F G A' with no alterations (sharps or flats).
However, since we base a mode's scales degrees on the Major Scale, and the Aeolian mode has a different intervallic series than the Major Scale, we alter the scale degrees, giving Aeolian the following:
1 2 ♭3 4 5 ♭6 ♭7
Another way to write the scale degrees are:
- Root (as is always the case)
- Major Second (2 semitones above the root)
- Minor Third (3 semitones above the root)
- Perfect Fourth (5 semitones above the root)
- Perfect Fifth (7 semitones above the root)
- Minor Sixth (8 semitones above the root)
- Minor Seventh (10 semitones above the root)
Let's listen to the A Aeolian mode against a droned A:
A quick clarification
If you happen to be coming from the article on the Ionian Mode or the Dorian Mode, you may realize that the white keys from C-C' (Ionian) are the same notes as the white keys from D-D' (Dorian) and the white keys from A-A'.
Ionian and Aeolian are both modes of the Major Scale. More specifically, C Ionian and A Aeolian both come from the C Major Scale. This means that, yes, they have the same notes. But their starting points (roots) are different. And this means a lot:
- Their intervallic series are different
- Their scale degrees are different
- Their qualities (major vs. minor) are different
- Their inherent chords are different
- Their functionalities are different
So even though C Ionian and A Aeolian are made up of exactly the same notes, they are different! This is the beginning of modal study.
The modal chords of the Aeolian mode
The Aeolian mode yields one triad and one tertian seventh chord. Much like the Dorian and Phrygian modes, they are:
- Minor triad 1 ♭3 5
- Minor seventh chord 1 ♭3 5 ♭7
Other common chords include:
- Sus2 1 2 5
- Sus4 1 4 5
- Min7sus4 1 4 5 ♭7
- Min♭6/9 1 ♭3 5 ♭6 9
Along with all the extensions beyond the major seventh chord, notably:
- Min9 1 ♭3 5 ♭7 9
- Min11 1 ♭3 5 ♭7 11
- Min♭13 1 ♭3 5 ♭7 ♭13
Functionality of Aeolian
The Aeolian Mode shows up with the vi chord (submediant) in diatonic harmony.
The Aeolian mode is often called the Natural Minor scale and is the “relative minor” to the major scale it's derived from.
For example, A Aeolian (A Natural Minor) is the relative minor of C Major (C Ionian).
One way to visualize this is if we build up a tertian seventh chord on A Aeolian, we have A C E G, which contains the C major triad (C E G).
The Aeolian mode has the Minor pentatonic scale within it. Adding in the minor sixth and the major second turns our minor pentatonic into an Aeolian mode.
Aeolian's Characteristic Tones
When looking for a mode's characteristic tone(s) (the tones that give it its flavor and differentiate it from other modes), it's a good idea to first look at the tritone intervals and half step intervals. It's also very important to look at the quality of the third (is it minor or major?)
Relating a mode to either Ionian (Major Scale) or Aeolian (Natural Minor Scale) can help us to determine characteristic tones as well. But since we can't really compare Aeolian to itself, we'll look at some other tones.
Personally, I would recommend memorizing the Aeolian mode and relating other minor modes to it.
The Major Scale's modes each have two half step intervals and one tritone interval.
One tritone interval could mean two tritone intervals. For example, B-F is a tritone and F-B is a tritone. Most of the time we'll look for the [one] tritone interval in the Major Scale modes.
Aeolian's tritone is between its major second and minor sixth. The half step intervals are between the major second/minor third and perfect fifth/minor sixth. Aeolian's third scale degree is minor.
So, the minor third tell us that Aeolian has a minor quality.
The major second in the tritone interval differentiates Aeolian from Phrygian.
The minor sixth in the tritone interval differentiates Aeolian from Dorian.
Once again, Aeolian, being the natural minor scale (the relative minor of Ionian), is a common scale (like Ionian) and thus is tough to characterize with one or two notes.
We could simply give Aeolian “dibs” over the minor seventh chord, but Dorian is used over that chord quite a bit too…
So let's spell out the characteristic tones before we get to Aeolian's modal chords:
- Major Second & Minor Sixth (tritone interval)
- Minor third (quality defining note)
- Minor seventh (just for the sake of relating it to Ionian)
Some more personal thoughts here, but I believe that the ♭6 is Aeolian's most characteristic tone. It's the avoid note. And it differentiates Aeolian from Dorian and both those modes are solid candidates for the minor seventh chord (Phrygian's ♭2 doesn't make it a great choice for the minor seventh chord, and so the distinction between Aeolian and Phrygian is not as important in tertian harmony…) Not a rock solid argument, only my belief, but I thought I'd share!
Let's take these into the next section.
Aeolian's Modal Chord
Building Aeolian's chord from its characteristic tones noted above, we'd have:
1 2 ♭3 ♭6 ♭7
Now that sounds a bit… clustered.
Why don't we try an extended minor seventh chord, raising the 2 and♭6 up an octave to help spread the voicing? That would look like:
1 ♭3 5 ♭7 9 ♭13
That's a lot of notes for one chord.
Oftentimes, the minor sixth is taught as an avoid note in the Aeolian mode since it creates a dissonant minor ninth interval with the perfect fifth. However, since the minor nine is what differentiates Aeolian from Dorian, I say we add it in the name of “modality.”
Let's get rid of that minor ninth interval instead by omitting the perfect fifth, giving us:
1 ♭3 ♭7 9 ♭13
I think that works out nicely. Far from perfect, by nicely…
When dealing with heptatonic modes, we can only truly get an absolutely “modal chord” when all seven of the notes are present within it. But the min♭13 (omit 5 and 11) chord gives us a strong sense of the mode Aeolian!
Practicing Aeolian and Modal Harmony
As with all modal practice, I prefer the pedal point method.
Pedal (drone a constant tone) the root of Aeolian, if you have a polyphonic instrument. And go through each of the scale degrees to hear the intervals they create against the root.
1 2 ♭3 4 5 ♭6 ♭7
If you have a monophonic instrument, try alternating between the root and each scale degree, one-by-one, to get a sense of each distinct interval.
Next, try droning the “modal chord.” In Aeolian's case, the min♭13 (omit 5 and 11) chord (wow that's a mouthful). Of course, this is only possible on a monophonic instrument. Although, arpeggios could work on monophonic instruments.
Go through the same exercise of relating every scale degree to the chord and listen to how each one compares.
Next, cycle through all possible intervals, playing them in unison with a droning root note. Pay special attention to the half step intervals against the root and the tritone intervals against the root.
Finally, have some fun creating modal chords with any of the Aeolian notes played with its root.
A common example in Modal Jazz is quartal harmony, or stacking fourths. In Aeolian's case, a stacked fourth tetrad would be:
1 4 ♭7 ♭3
Writing and Composing with Aeolian
A quick note on tonal harmony vs. modal harmony
When composing with tonal harmony, we have “circular cadences.” Resolutions that often happen while moving around the circle of fifths (or fourths, depending on how you look at it).
For example, the iii-vi-ii-V-I chord progression in C Major would be:
- Amin7 (or A7 as a common alteration)
Those chords' roots move circularly counter-clockwise through the circle of fifths.
This is tonal (functional) harmony.
Modal harmony has linear, or lateral cadential movement. Often times the best cadential chord is built on the second or seventh scale degree of the mode.
In modal harmony, we must take great care as to not seek out the dominant V chord, or to play too many chords other than the tonic. Doing so will result in our ears hearing tonal harmony, as it's so commonly used in music.
We must reference the tonic chord very often to ensure that we are indeed in that specific mode!
In modal harmony, we don't absolutely need to use all the notes in the mode, but it helps to further specify, unambiguously, which mode we're in. For example, Aeolian without the minor sixth is the same as Dorian without the major sixth. Similarly, Aeolian without the major second is the same as Phrygian without the minor second.
Aeolian's modal cadences
We want to look step-wise to find the most cadential chords. The more cadential chords are chords that:
- are major in quality.
- contain the characteristic note.
- do not contain a tritone interval (making them sound dominant)
Note that chords a third away from a modes root do not provide much tension and are often merely heard as “changes of color” (especially in tertian harmony).
Note also that chords a fourth/fifth away tend to lead us out of modal harmony and back toward the circular nature of tonal harmony.
So the most cadential chord in Aeolian modal harmony is the♭VII (Mixolydian triad).
Note here that it's the triad that is the cadential chord and not the♭VII dominant seventh chord, which would have the tendency to send us into tonal harmony vi-V-and finally to I.
- It's a whole step away (lateral movement)
- It has a major third
- However, it does not contain the most characteristic tone (♭6)
Note that the ♭VII 7 chord does contain Aeolian's most characteristic tone, but it has a strong tendency of bringing us into tonal harmony, as the now dominant7 chord wants to resolve to its Major tonic.
Stuck between a rock and a hard place, as the ii(min7flat5) (Locrian chord) also wants to kick us out of modal harmony and send us to a tonal centre. This is because the ii(min7flat5) has a tritone interval between its 1-♭5.
One more thing to note is that Aeolian itself is the relative minor of a functional major tonic. And so care must be taken to repeatedly remind the listener that we are indeed playing modally.
Of course, this is all just for your information and not set in stone, if it sounds good, play it!
I invite you to write a song based on the Aeolian mode. For more information, check out my article on writing and playing modally.
Chances are, even if you don't know the mode, you've been using it plenty in writing and playing music.
Let me know what you come up with while writing with the Aeolian mode! And if there's anything else you'd like to add to the discussion of the Aeolian mode, please leave a message in the comment section!
As always, thank you for reading and for your support,