The dominant key of A major is E major.
In music theory, the dominant is the fifth scale degree of a diatonic scale, and it plays a crucial role in harmony and tonality. For any major key, its dominant key will always be the major key built on the fifth note of its scale.
Understanding the Dominant in Music
The dominant, often referred to as the V (five) chord or V key, creates a strong sense of tension that naturally resolves back to the tonic (the root of the key, or I chord/key). This fundamental relationship is a cornerstone of Western music harmony, driving chord progressions and outlining harmonic movement.
For the A major scale, the notes are A, B, C♯, D, E, F♯, G♯, A. Counting five steps up from A (A-B-C♯-D-E) lands on E. Therefore, the dominant key is E major.
Key Relationships in A Major
Beyond the dominant, other scale degrees also have specific names and associated keys or chord qualities that are fundamental to understanding the overall tonal landscape of A major. Here's a quick overview of some important relationships:
| Scale Degree | Name | Key/Chord Quality |
|---|---|---|
| I | Tonic | A Major |
| V | Dominant | E Major |
| VI | Submediant | F-sharp minor |
| VII° | Leading-tone | G-sharp diminished |
The submediant (VI) is the sixth degree of the scale, often forming a relative minor key, while the leading-tone (VII°) is the seventh degree, typically a diminished chord that strongly pulls back to the tonic.
Why the Dominant is Important
- Harmonic Drive: The dominant chord (E major in the key of A major) creates a strong pull towards the tonic, making it essential for establishing and returning to the home key.
- Modulation: Dominant keys are frequently used as pivot points for modulation, allowing composers to transition smoothly from one key to another. For instance, a piece in A major might modulate to E major, its dominant, before returning to A major.
- Cadences: Dominant chords are integral to perfect authentic cadences (V-I), which provide a definitive sense of conclusion at the end of musical phrases.
Understanding the dominant key is vital for musicians, composers, and anyone studying music theory, as it unlocks a deeper comprehension of harmonic progression and musical structure.
