Understanding Chords Made Up of Scale Degrees 1, 4, and Flat-7

Introduction

Understanding chords involved in western music theory can sometimes challenge our conventional approaches. This article explores a specific type of chord made up of scale degrees 1, 4, and flat-7, commonly known as a dominant seventh chord, and delves into its composition and usage within the framework of quartal harmony and suspensions.

Understanding the Chord: Dominant Seventh Chord

A dominant seventh chord is a fundamental component of western music and is represented by the combination of the root, a perfect fourth above the root, and a flat seventh. Let's examine two examples to illustrate this concept:

C-F-Bb

This chord corresponds to the C mixolydian scale, with C as the root (1), F as the fourth (4), and Bb as the flat seventh (b7). The chord can be identified as a C7 chord, which is a C dominant seventh. This particular chord follows the pattern of stacking perfect fourths to form a dominant seventh sound.

A-D-G

Similarly, the chord A-D-G corresponds to the A mixolydian scale, with A as the root (1), D as the fourth (4), and G as the flat seventh (b7). This chord can be identified as an A7 chord, an A dominant seventh. The combination of the root, a perfect fourth, and a flat seventh creates the characteristic dominant seventh sound.

Quartal Harmony

Chords such as C-F-Bb and A-D-G fall under the category of quartal harmony. This term refers to chords constructed from intervals of perfect fourths, as opposed to the more traditional approach of stacking thirds. Quartal harmony is less common in western music but has gained popularity in contemporary music and jazz.

One limitation of using quartal harmony is that these chords lack a clear root, which makes it challenging to categorize them strictly within the framework of traditional chord theory. This rootless quality is one reason why naming these chords can be difficult. In many cases, these chords might be part of a 4–3 suspension, meaning that the "4" (F in the C-F-Bb chord or D in the A-D-G chord) could resolve to the "3" (E in the C-F-Bb chord or G in the A-D-G chord) in the next chord.

Contextual Definitions

Because these chords lack a clear root, their definition is highly context-dependent. Without knowing the progression to which the chord belongs, it is impossible to determine the root and whether the chord is a C7, A7, or any other chord type. For example, in the case of E-G-C, it is most likely that C is the root, although there is a small chance that it is an E minor chord with the fifth displaced temporarily.

Conclusion

In summary, chords made up of scale degrees 1, 4, and flat-7, such as C-F-Bb and A-D-G, are primary examples of dominant seventh chords in the context of quartal harmony. They differ from traditional chord structures and rely heavily on contextual analysis. Understanding these chords involves recognizing their formation and extensions within a broader harmonic framework, which can include suspensions and other complex harmonic progressions.

Keywords: dominant seventh chord, quartal harmony, suspension