It can be difficult to keep track of all of the different types of chords, as well as their relationships to each other. However, understanding different chord qualities is important for songwriting, improvising, or just all around being a musician. I’ve found it helpful to think of different chord types as a spectrum, much like the color spectrum. Below is a simple version of this spectrum that consists only of the six most common chord qualities.
A Broad Look
On one end of the above chard, we have chords primarily built upon minor thirds. On the other end we have chords primarily built upon major thirds, and in the middle we have chords that split the difference. The chords on either end are extreme opposites of each other, and the differences will grow less stark as we move towards the middle of the spectrum.
A QUICK NOTE: as we analyze the different types of chords in the above chart, we will be using the root position triad versions of the chords as the frame of reference, as is common practice. The concepts discussed in this piece are equally applicable to inversions of the triads and denser versions of the chords. However, minimalist root position versions of the chords will be used for all examples for the purpose of the clear illustration.
On the end of the left side of the spectrum (which I like to think of as the minor side), we have diminished chords. Diminished chords contain a triad of two stacked minor thirds, which makes them more minor than minor chords and thus places them on the far end of the spectrum. Diminished chords sound darkly dissonant and occur naturally on the seventh degree of the major scale.
After diminished chords, we have minor chords. Minor triads consist of a minor third followed by a major third. So while they contain an equal amount of minor and major thirds, the fact the minor third occurs first makes it the definitive of the two thirds and ultimately places minor chords on the left side of the chord spectrum. Although minor chords share the darkness heard in diminished chords, they are much more consonant are used far more widely in popular music. Minor chords occur naturally on the second, third, and sixth, scales degrees of the major scale.
In the middle, we have dominant and suspended chords. Dominant and suspended chords walk the line between major and minor, and don’t fit neatly into either category. Dominant chords are built upon a major triad, but have at least at a minor seventh interval stacked on top of the triad. That exact combination of a major triad and a minor seventh form a dominant seventh chord, which is both the simplest kind of dominant chord and the foundation of all the other dominant chords.
Altogether, a dominant seventh chord consists of one major third and two minor thirds. When played in root position, the major third is the first and therefore definitive third, but it’s still outnumbered by the minor thirds. This creates a chord that essentially splits the difference between major and minor and thus falls in the exact middle of the chord spectrum. Dominant chords sound gritty, in your face, are fairly dissonant, and usually really want to resolve to a major stable-sounding chord. They occur naturally on the fifth scale degree of the major scale.
Suspended chords are the only chords discussed in this piece that break the pattern of stacked thirds. Suspend chords contain and a root note and a fifth just like all of the chords we’re going to go over, but instead of a third, it has either a major second or a perfect fourth. Suspended chords with a major second are called a suspended-second (or sus2) and the somewhat more common variety of suspended chord with a perfect fourth is called a suspended-fourth (or sus4).
Neither the perfect fourth nor the major second (despite its name) make the chord lean inherently major or minor, which ultimately places suspended chords in the middle of the spectrum, along with dominant chords. Suspended chords sound tense, ambiguous, and bittersweet. Sus2 chords can be built over every scale degree in the major scale except the third and seventh, and sus4 chords can be built over every scale degree in the major scale except the fourth and seventh.
Moving to the right side of the spectrum, we have major chords. Major chords are the exact opposite of minor chords; while minor chords consist of a minor third followed by a major third, major chords consist of a major third followed by a minor third. The two are essentially mirror images of each other. Because of this structural similarity, major are in many ways the brighter, happier counterpart of minor chords. Both are consonant chords with similar harmonic functions, but with pretty much opposite moods. Major chords occur naturally on the first, fourth, and fifth scale degrees of the major scale.
After major chords come augmented chords, which occupy the far-left end of the chord spectrum. Augmented chords consist of two stacked major thirds, which makes them the polar opposite of diminished chords. Augmented chords are also the only chord type discussed in this section that will never occur diatonically, which means that every augmented chord is going to contain at least one note outside of the key. This fact, paired with augmented chords’ jarring dissonance, makes them the least commonly used of the main chord types. However, augmented chords can still be heard in all sorts of music and have been used by everyone from The Beatles to Stevie Wonder to Beethoven.
A More In-Depth Look
Below is a slightly more fleshed out version of the earlier chart. It is built off of the previous chart, but is adjusted to accommodate an added seventh to some of the chord qualities. This creates a more nuanced look at the chord spectrum that accounts for denser harmonies. Although not all of the chord types on it are particularly common, they all see far enough usage to be worth understanding. The below chart can of course be ever further fleshed out to include more nuanced differences, but the information already on it is plenty to get you started.
ANOTHER QUICK NOTE: Although we are now looking at chords that inherently denser than triads, we will still be examining all of the chords discussed through the framework of looking at them in root position. Just as with the previous section, everything discussed is still equally applicable to inversions of these chords.
Starting on the left end of the above chart, the first new chord we come across is the full diminished. A full diminished chord (also known as a diminished seventh), is a diminished triad with a diminished seventh interval (which is enharmonic with a major sixth) stacked on top. This adds up to a total of four minor thirds within the chord, thus placing it on the far left side of even this more nuanced look at the chord spectrum. Full diminished chords never occur diatonically, but they are a notable part of many pieces of music written in harmonic minor modes.
Following the full diminished chord is the highly similar half-diminished chord. The half-diminished chord (sometimes referred to as a minor seventh flat five) is a diminished triad with an ordinary minor seventh stacked on top. This means that a full diminished and a half-diminished chord are exactly the same, except that the seventh in the half-diminished is a half-step higher than the seventh in the full diminished. Altogether, a half-diminished chord consists of two minor thirds followed by a major third at the very top. The half-diminished chord occurs naturally on the seventh scale degree of the major scale.
The next new chord in the minor major seventh, which sits with dominant and suspended chords in the middle of the spectrum. Minor major seventh chords are the conceptual inverse of dominant seventh chords; while a dominant seventh chord consists of a minor seventh stacked on top of a major trial, a minor major seventh consists of a major seventh stacked on top of a minor triad. Altogether, a minor major seventh chord contains one minor third and two major thirds, with the minor third being the definitive one. The minor major seventh chord will never occur diatonically, but it can be built off of the first scale degree in both the harmonic minor scale and the melodic minor scale.
The final newly introduced chord is the augmented seventh. An augmented seventh is an augmented triad with a minor seventh interval stacked on top. This gives the chord a total of two major thirds and one diminished third, the latter of which is enharmonic with a major second. The diminished third places the augmented seventh left of a simple augmented chord on the chord spectrum, but its augmented triad makes it still lean right of a simple major chord. The augmented seventh chord does not occur diatonically and is not used particularly often in popular music. However its harsh, striking sound gives it a lot of character, and it can be a highly effective choice when used tastefully.
The other chords on the above chart, such as major, minor, and suspended chords, do not become particularly complicated by the addition of sevenths. A major-seventh and a minor-seventh will sound richer and distinct from their triadic equivalents, but will ultimately function in the same way and occupy the same spaces on the chord spectrum.
