Understanding 7th Chords: Major or Minor

Understanding whether 7th chords are major or minor can be a complex topic, especially when considering the different types of 7th chords and their scales. This article will delve into the nuances of 7th chords, clarifying whether they are major or minor, and how to distinguish between them.

Types of 7th Chords

7th chords are simply chords that include the seventh note of the scale, creating a quadruple of notes or a tetrad. These chords can be built based on different types of triads (major, minor, augmented, diminished) and will result in various 7th chords. Let's explore these in detail.

Major 7th Chord (maj7)

A major 7th chord is built on a major triad with a major 7th interval. This chord uses the notes 1, 3, 5, and 7 of the major scale. For example, a C major 7th chord is C-E-G-B.

Minor 7th Chord (m7)

A minor 7th chord is built on a minor triad with a minor 7th interval. This chord uses the notes 1, 3, 5, and 7 of the natural minor (or harmonic and melodic minor) scale. For example, a C minor 7th chord is C-Eb-G-Bb.

Dominant 7th Chord (7)

A dominant 7th chord is built on a major triad with a minor 7th interval. The dominant 7th chord is commonly found in blues and jazz music. For example, a C dominant 7th chord is C-E-G-Bb.

Minor-Major 7th Chord (mM7)

A minor-major 7th chord is a specific type of 7th chord built on a minor triad with a major 7th interval. This chord is also known as a Hitchcock chord and is commonly used in film scores, particularly the score for Psycho. For example, a C minor-major 7th chord is C-Eb-G-B.

Diminished 7th Chord (dim7)

A diminished 7th chord is built on a diminished triad with a diminished 7th interval. This chord is often used in jazz and classical music. For example, a C diminished 7th chord is C-Eb-Gb-Bbb.

Augmented 7th Chord (aug7/maj7#5)

An augmented 7th chord can be built on both an augmented triad with a major 7th interval or an augmented triad with a minor 7th interval (known as an altered dominant). For example, a C augmented 7th chord is C-E-G#-Bb.

Major or Minor?

The term "major or minor" when referring to 7th chords can be misleading. While a major 7th chord is major, and a minor 7th chord is minor, there are other types of 7th chords that do not fit neatly into these terms.

Major 7th vs. Minor 7th: Interval Analysis

From an interval perspective:

A major 7th interval is a half-step smaller than an octave, from A to G, B to A, C to B. A minor 7th interval is a whole step smaller than an octave, from A to G, B to A, C to Bb.

However, when analyzing 7th chords, it is crucial to look at both the third and the seventh of the chord to determine its quality:

Major Major 7th Chord (maj7)

A major major 7th chord consists of a major third and a major seventh. For example:

C-major major 7th  C-E-G-B

Major Minor 7th Chord (maj7)

A major minor 7th chord consists of a major third and a minor seventh. For example:

C-major minor 7th  C-E-G-Bb

Minor Major 7th Chord (mM7)

A minor major 7th chord consists of a minor third and a major seventh. For example:

C-minor major 7th  C-Eb-G-B

Minor Minor 7th Chord (m7)

A minor minor 7th chord consists of a minor third and a minor seventh. For example:

C-minor minor 7th  C-Eb-G-Bb

Conclusion

Understanding 7th chords is vital for musicians, composers, and music enthusiasts. Whether you are a beginner or a more advanced musician, knowing the differences between major and minor 7th chords can greatly enhance your musical skills. By understanding the underlying intervals and chord construction, you can better appreciate the rich harmonic landscape of music.

Remember, whether a 7th chord is major or minor depends not just on the seventh interval but on the interplay between the third and the seventh. This interplay is what gives 7th chords their unique and versatile qualities.