Seventh Chords

7.0  Seventh Chords

Seventh Chords, like most musical structures, require a complete understanding and facility with scales and triads. If you are not fully comfortable with those ideas, be aware that seventh chords can be somewhat difficult.  It is a good idea to practice your fundamentals on a regular basis!

7.1 Overview

Recall that Western harmony is built using the tertian system, meaning that chords (or "verticalities") are built of thirds. Therefore it is possible to build structures that include more than just a 5^th and a 3^rd above the bass. (Note: These structures all contain dissonant intervals once we've built beyond the 5^th, as the example below illustrates):

 

As the example above illustrates, once we build structures beyond the triad (including 11^th and 13^th chords, which are not included in the above example), all of our chords will contain dissonant intervals.

As more and more dissonant intervals are added to the chord, the less stable the structure becomes, which makes "tall" chords perfect for idioms like jazz and other twentieth-century musics.

7.2  Nomenclature

While chords with intervals beyond the 7^th are possible, we will save a detailed discussion of them for later semesters. Seventh chords have a very strict system of nomenclature while 9^th, 11^th, and 13^th chords do not, so we will spend some time this semester learning how to identify seventh chords.

In many ways, identifying a seventh chord is a simple and straightforward process, requiring two steps:

A. Identify the quality of the triad (1-3-5 in the structure)

B. Identify the quality of the seventh above the root

Therefore, a chord built with thirds built on F (F-A-C-E) could be analyzed as follows:

 

We therefore identify that chord as an "F major major 7^th chord," or "FMM7" for short.

By the same token, if we lower the third and the seventh of the chord the qualities of the triad and the seventh will change, yielding:

 

7.3  Shorthand

Certain instances of the seventh chord are so common that they have their own abbreviations (or shorthand). They are listed below:

If the triad is	and the seventh is	then we abbreviate it with:
Major	Major	<root> Major 7th
Minor	Minor	<root> Minor 7th
Diminished	Diminished	<root> Diminished 7th

Memorize these abbreviations; they are used very commonly throughout the industry.

7.4  Inversions

Seventh chords can be inverted in the same way triads can be inverted. The same principles apply. The root remains the root, regardless of its actual position in the chord, but numbers are used to indicate the disposition of intervals above the bass, as the example below shows:

 

7.41   Inversion Shorthand

In practice, the above method of identifying seventh chord inversions works perfectly well. However, it is convention to abbreviate using the following conventions:

 

BT"> In the first example the number "3" is omitted, while in the second two, the "6" is left out.

Additionally, root position seventh chords are simply abbreviated as "7." Therefore, a G major major 7^th chord would be written as G7.

Memorize these abbreviations, as they are commonly used throughout the industry.

7.5  Dissonance Management

Dissonant intervals tend to require resolution to consonant ones. While dissonance is not inherently a bad thing, in common practice it is viewed as being a problem in need of resolution.

The example below illustrates a dissonance and its resolution:

 

Dissonant pitches tend to want to resolve by step, and the seventh is no exception. Specifically, sevenths resolve downward by step to a consonant interval (in this example, to a sixth).