A seventh chord is an intricate harmonic structure created by adding a seventh scale degree to the top of a major triad. This gives the chord its unique sound and opens up new opportunities in harmony.
Seventh chords can be identified by their root, the qualities of their triad and seventh, and pitch classes that occur in bass voice (which will be discussed further in Inversions and Figured Bass chapter). Most textbooks identify them by the type and quality of triad/seventh combination they contain.
Major Seventh
The major seventh chord is an essential component of many genres of music – from classical to rock and everything in between – adding emotion and complexity to progressions, while creating tension within songs as well.
Seventh chords constructed using me and le features a major triad and major seventh, while those composed using dominator/reservoir have a dominant/subdominant trio and diminished seventh, both written in musical notation as maj7/ma7 respectively.
A minor seventh chord can be created by flattening out one of the fifths of a diminished triad, creating a half-diminished seventh above its root. You might see this chord in blues or jazz music.
Minor Seventh
Chords featuring sevenths add dissonant notes, making them more complex than triadic chords and creating spelling and understanding issues for them. A Cm7 could appear on sheet music either as CM7 or Cm7 depending on its version; you should become acquainted with all variations so you can select the most suitable option when needed.
There are three seventh chord qualities with perfect fifths between their root and fifth: minor seventh, major-minor seventh, and fully diminished. Two other seventh chord qualities based on diminished triads: half-diminished adds a minor seventh while fully diminished adds major sevenths; each quality serves a unique function in various musical genres.
Dominant Seventh
Dominant seventh chords are composed of a major triad and minor third above the root, creating an entirely unique sound from major chords. Dominant seventh chords can create dramatic effects with their distinctive sound.
The dominant seventh chord type is one of the most widespread found across most genres of music; you will frequently come across them when listening to blues music as well.
Seventh chords can be identified both formally and by their constituent triad and seventh components; they can also be abbreviated. For instance, G7sus4 refers to a dominant seventh chord featuring both major triad elements and diminished seventh above its root note.
The chart below presents the most commonly found open shapes of dominant seventh chords. Experiment with playing this chord progression to get acquainted with them and to help stretch your fingers.
Major Inversion
When a major triad chord in its first inversion with its fifth chord tone in the bass is altered so as to have its third note (instead of root) be inverted, this forms what is known as a 6/4 chord. Doubling either root or third note should only be done as necessary as this can alter its function and identity, destabilizing the harmony’s function and meaning.
When chords are written out using slash notation, such as G/D or A/C#, this indicates you should play them in their second inversion position. A seventh chord with its root in the bass is often called root position; for this reason it is advised that you learn inverting chords you learn in order to create unique piano chord progressions.
Minor Inversion
Minor chord inversion is an effective way to add authenticity and depth to your chords. It works by rearrangeing the interval structure of a minor triad to place its third in the bass while its fifth remains above it, creating a bassy minor chord with sharper minor tones similar to what would be found in major chords.
To invert a chord, simply raise the lowest note by one octave – this will create the first inversion and you can play it as you would any root position chord.
When inverting a triad, always double the root tone when inverting it; any other chord tone doubling could obscure its identity as a triad chord.