Aeolian Mode

Aeolian is the natural minor scale. This is not an obscure modal sound — it's the foundation of minor key music in Western tradition for centuries. When you're in a minor key and haven't altered the scale, you're in Aeolian. Most rock ballads, metal, and minor key classical music use it as the primary scale.

Construction

The sixth mode of the major scale — starts on the 6th degree.
A Aeolian = C major scale starting on A:
A B C D E F G A

Formula: 1  2  ♭3  4  5  ♭6  ♭7
Step pattern: W - H - W - W - H - W - W

A natural minor has the same notes as C major — they're relative keys. But with A as the tonal centre, the minor character comes through: the minor third (C) and minor sixth (F) give it the darker, sadder quality.

Key Scales

A Aeolian:  A B C D E F G A
E Aeolian:  E F# G A B C D E
D Aeolian:  D E F G A B♭ C D
G Aeolian:  G A B♭ C D E♭ F G

Sound and Character

Sad, serious, introspective — the "plain" minor sound. Most people recognise it as simply "minor" without any modal qualification. The flatted 6th (F in A Aeolian) contributes particularly to its melancholy quality. Compare to Dorian (which has a natural 6th and therefore a warmer minor sound) — the difference between Dorian and Aeolian is one note, but Aeolian sounds more gloomy.

"Stairway to Heaven," "Nothing Else Matters," "Mad World," the slow sections of countless metal tracks — Aeolian is the dominant sound of serious minor key rock. In classical music it corresponds to the natural minor mode, though composers would raise the 6th and 7th (getting melodic minor) when ascending.

The Aeolian Progression

Characteristic Aeolian progressions:
i — ♭VII — ♭VI — ♭VII    (often repeated, very common in rock)
In A: Am — G — F — G

i — ♭VI — ♭III — ♭VII
In A: Am — F — C — G

The ♭VII chord (G major in A Aeolian) is one of the most characteristic sounds — it's a major chord borrowed from the relative major. The movement from F to G to Am (♭VI → ♭VII → i) appears in hundreds of rock and pop songs.

Aeolian vs. Dorian

The only difference is the 6th: Dorian has a natural 6th (B natural in A), Aeolian has a flatted 6th (F in A). This determines which IV chord you get: Dorian has a major IV (D major in A Dorian), Aeolian has a minor iv (Dm in A Aeolian) and a ♭VI (F major). The Dorian IV is brighter; the Aeolian ♭VI is more melancholic. Choose based on the mood you're after.