Triads are the essential building blocks of harmony, and understanding them is key to understanding music theory.
So, let’s explore the diatonic triads within the C minor scale. We’ll also look at how the different types of minor scales — natural, harmonic, and melodic — impact how these triads are formed.
The C Minor Scale: A Foundation
Before we dive into the triads, let’s cover the three different forms of the C minor scale, since they each have a slightly different flavor.
The C Natural Minor Scale
The C natural minor scale consists of these notes: C-D-Eb-F-G-Ab-Bb-C. The formula for any natural minor scale is root, 2, b3, 4, 5, b6, b7.
The flat third, sixth, and seventh are what gives the minor scale its characteristic sound.
The C Harmonic Minor Scale
The C harmonic minor scale is: C-D-Eb-F-G-Ab-B-C. The only difference between the harmonic minor and the natural minor is that the seventh degree is raised a half step.
The C Melodic Minor Scale
The ascending C melodic minor scale contains the notes: C-D-Eb-F-G-A-B-C. When ascending, both the sixth and seventh degrees are raised.
When descending, however, the melodic minor scale is the same as the natural minor scale.
Diatonic Triads in C Natural Minor
Diatonic triads are built by stacking thirds – that is, skipping notes – on each degree of a scale. Each triad contains a root, a third, and a fifth.
Here are the triads in the C natural minor scale:
- i: C minor (C-Eb-G) – minor triad
- iiº: D diminished (D-F-Ab) – diminished triad
- III: Eb major (Eb-G-Bb) – major triad
- iv: F minor (F-Ab-C) – minor triad
- v: G minor (G-Bb-D) – minor triad
- VI: Ab major (Ab-C-Eb) – major triad
- VII: Bb major (Bb-D-F) – major triad
Notice the pattern of chord qualities: minor, diminished, Major, minor, minor, Major, Major.
Diatonic Triads in C Harmonic and Melodic Minor
When you move away from the C natural minor scale, the triads change a little.
C Harmonic Minor
In the harmonic minor scale, the seventh degree is raised by one half step. This changes the quality of two triads:
- v: G major (G-B-D) – becomes a major triad
- viiº: B diminished (B-D-F) – becomes a diminished triad
C Melodic Minor (Ascending)
In the ascending form of the melodic minor scale, both the sixth and seventh degrees are raised by one half step. This alters the quality of two triads:
- iv: F major (F-A-C) – becomes a major triad
- v: G major (G-B-D) – becomes a major triad
Summary
Knowing the triad patterns for C minor’s natural, harmonic, and melodic forms is essential for understanding and composing music in this key. Now, go forth and explore chord progressions and other applications!