7th chords add color and character to otherwise bland pop chord progressions, are the basis of jazz harmony, and are found frequently in classical repertoire. But what are they? And why bother learning them? In this article we will learn the most common 7th chords and discuss the motivation for learning them.
So what is a 7th chord? The short definition: A 7th chord is an extension of a triad that includes a note a 7th above the root of the chord. The next section will clarify some of that terminology.
What Are 7th Chords
A triad in music is a chord made of 3 notes. Generally the 3 notes form a major, minor, diminished, or augmented chord.
A triad is typically constructed from the 1st also known as the root, 3rd, and 5th scale degrees of it’s corresponding scale. For example the D major triad is highlighted below in blue and taken from the D major scale.
A 7th chord extends a triad by adding an interval of a 7th above the root. All 7th chords have 4 notes. Highlighted in blue below is a 7th chord. In this case C♯ is a 7th above the root, D.
7th Chord Terminology and Naming Convention
The terminology and naming convention for chords is somewhat inconsistent but in general:
- A capital “M” stands for major, a lowercase “m” for minor, “dim” for diminished, and “aug” for augmented.
- Assume a chord is major unless marked otherwise (m, dim, aug).
- D = D major
- Dm = D minor, etc.
- The root and “1” of a chord refer to the same note – the note in the name of the chord. For example, the root or 1 of D7 is “D”
- Assume the 7th is a minor 7th above the root unless marked otherwise. (Relearn your intervals if you are unfamiliar with the following: m7, M7, m3, tritone, etc).
Don’t worry about memorizing these rules. We will reinforce them as we review the 5 most common 7th chords below.
The Major 7 chord – M7 – maj7
Think sweet sounding. Below is a D major chord with a major 7. So that’s DMM7. But recall from our naming convention that a chord is major unless indicated otherwise so that first “M” is dropped leaving use with DM7
Note that it includes D, F♯, A – a major chord and F♯, A, C♯ a minor chord. I think this mixture gives the chord it’s sweetness.
The Dominant 7 Chord – 7
Think tension and resolution. Below is a D major chord with a minor 7 above the root. So DMm7, but recall that chords are assumed to be major and 7th’s are assumed to be minor. We end with simply D7.
The dominant 7 chord is the most common 7 chord. It is used especially at the end of a phrase to create tension before resolving to a chord a 4th above (or 5th below) its root.
For example, D7 often resolves to a G major or minor chord. The dominant 7 chord creates its sense of tension and resolution because:
- There is a tritone, one of the most tense intervals, between the 3rd and 7th scale degrees. For example F♯ and C are a tritone apart in a D7 chord.
- The 3rd and 7th, in our case F♯ and C, are both half step away from G and B respectively. A movement of a half step creates a sense of resolution.
These principles are the beginning of functional harmony, which is the understanding of how chords relate to one another. Understanding functional harmony is like moving from understanding words (chords) to sentences (functional harmony).
You’ll hear dominant chords often at the end of a classical piece for the grand finale.
The Minor 7 Chord – m7 – min7
Think dark and mellow. The chord below is a D minor chord with a minor seventh. So Dmm7, but again the 7 is assumed to be minor, leaving us with just Dm7.
I think the chord has a mellow sound because 3 (F), 5 (A), and 7 (C) spell out a major chord. So it is like a major chord stacked on top of a minor chord. For example, Dm7 is the F major chord stacked on top of the D minor chord.
The Minor 7 ♭5 – m7♭5 – ø7
Think mysterious. Below is an example of the Dm7♭5 chord. The ♭5 indicates that the 5 has been flattened from A in the usual Dm7 chord to A♭.
There are many names and symbols for this chord. This includes m7♭5, ø7, or half diminished. Often a half diminished chord resolves to a major chord up a half-step.
The Fully Diminished 7 – dim7 – o7
Think edgy and tense. The fully diminished 7 chord consists of a diminished chord with a diminished 7 on top. A diminished interval is a minor interval that has been flattened a half step. Below is the D fully diminished 7 or Ddim7 chord.
The chord is quite symmetrical; It is a stack of m3’s and contains two tritones
Because of its symmetry it can resolve in many directions; most commonly it resolves to a major or minor chord up a half step.
Each 7th chord has its unique For an explanation of 7th chords that includes auditory examples I recommend this video from Pianote.
There are other 7th chords as the augmented 7 – aug 7 – or the minor major 7 – mM7. However, these chords are used infrequently so we won’t discuss them here.
Why Learn 7th Chords
It’s hard for me to motivate myself to learn theory when I don’t understand the application. So here are the reasons why you may invest in learning 7th chords. See if any of these apply to your music goals. And if not, maybe you shouldn’t invest your time in learning them!
You Are Interested in Jazz Piano
Jazz music is littered with not only 7th chords, but also more complex chords such as 9th, 11th, and 13ths. For example listen to this version of Autumn Leaves.
You Are Interested in Adding Color to Pop Progressions
I love Jake Lizzio’s video on 7th chords. The video cuts to 10:50 where he starts spicing up a simple chord progression with some 7th chords. He creates a loop track that is surprisingly rich even though it is just 4 chords thanks in part to his use of 7th chords. At 11:50 he actually starts groovin’.
You can practice adding color to pop chords by trying out 7th chords on some of your favorite chord progressions. For example:
Am C G Em Am -> Am7 CM7 G Em7 Am7
It takes some trial and error, I didn’t make the G chord a G7 because I didn’t like it next to Em7 and I didn’t make it GM7 because the 7 of GM7, F♯, is not in the key of Am.
You Are Interested in Learning Sheet Music Faster
Especially in challenging Romantic Period repertoire (1800’s) and later, 7th chords are common. Consider the opening of Rachmaninoff’s second piano concerto below. (Notice that the D♭M7 chord has an F in the base instead of a D♭. When the bottom note of a chord isn’t the root, that is called an inversion.)
The ability to recognize 7th chords on sight is doubly beneficial because it allows you to clump data quickly in your mind throughout the learning process, Also it allows you to store the music in larger chunks throughout the memorization process.
So now you should be comfortable with the main types of 7th chords, which includes M7, 7, m7, m7♭5, and dim7. You should also understand the value of learning 7th chords across multiple genres and be able to make an educated decision about if or how you want to learn them.
I’d place 7th chords in the mid-late intermediate pianist level. If you are at this level, perhaps you would enjoy rethinking how many hours a day you should practice.