After learning major and minor triads, the next step should be learning seventh chords – chords comprised of three triads plus an additional note that forms an interval with its root note.
To understand seventh chords, it’s essential that you understand movable shapes and can count intervals effectively. With these skills in place, chord construction becomes effortless!
Major
Addition of a seventh chord can give it a distinct character; often called color. It is frequently heard in rock and blues music.
Major seventh chords can also be created from minor triads by transposing one of their notes by half steps up or down; for example, an F triad becomes an Fmaj7 chord by moving its second note up one note (to E).
There are other kinds of seventh chords besides major, minor, or dominant that don’t fall into these three categories. These include augmented, diminished and half-diminished seventh chords. Although these less commonly used chords may sound dissonant or strange, they’re not intended as mainstay structural chords in songs; rather used more as passing chords between chords in songs – known as “tertian chords” due to being constructed from sequences of major third intervals (4 semitones) and minor third intervals (3 semitones), which makes up each shape in turn tertian seventh chord shapes:
Minor
A minor seventh chord follows similar principles to its major triad counterpart, with only slight variance being that its seventh interval added to the root note is flattened rather than round – this gives it more of an bluesy, homesick or spicy sound, making it suitable as V chord leading back into I.
As one might imagine, G7 chords are most prevalent in blues and folk music. For instance, The Rolling Stones used G7 chords in “(I Can’t Get No) Satisfaction,” while Doors and Blue Oyster Cult both utilized B7 chords in their genre-bending rock music.
Minor major seventh chords, which feature a major third but minor seventh, are another less-common seventh chord type, though they can add tension-and-release when used together with straight minor chords.
Dominant
As its name suggests, the dominant seventh chord has an authoritative presence due to containing both major and minor third intervals – two notes six half steps apart – which create an electric sound when played.
Its strength lies in creating tension that needs to be resolved musically in a melodic cadence; you’ll often see this chord type used in blues music as well as pop and rock genres.
Dominant seventh chords resemble major chords in appearance and structure, yet add an unexpected sound due to their addition of seventh tone chords that is often described as being “heavy”.
V7
Seventh chords introduce more dissonance into a song than their triad counterparts; however, when used appropriately to preserve tonic harmony they can add an extra splash of color.
Contrary to triads, seventh chords can be constructed on any scale degree and can include major and minor intervals. Some commonly-used seventh chords include major/minor 7ths, diminished 7ths and half-diminished (7ths).
Like triads, sevenths usually resolve by either a falling fifth or rising fourth root motion, though in contrast with these the seventh of a VII chord can often come into being as an independent note that originates in its preceding I (or V) chord; as a result of this the seventh in ii6/5/7 chords often step down towards their accompanying V chord leading tone in an intuitive fashion.
The ii7 chord is an integral component of functional harmony as it serves as a tonic substitute in cadential progressions. This is because its intervals match those found in tonic triad, but with an additional dominant seventh added.