Seventh chords are used extensively in blues, funk and jazz music. Their dissonant sound creates tension that must be resolved.
Seventh chords can also be invaluable tools for driving to the tonic note or chord, making the melody of any given tonic note or chord more prominent. There are various kinds of seventh chords.
Triads and Seventh Chords
A seventh chord is a four-note chord composed of three triads joined together with an added pitch sounding one seventh above its root note. They offer richer harmonic structure but may also be more complex and dissonant than their triadic counterparts.
Triads and seventh chords both can be built up in thirds. When both types match up exactly, they’re often simply referred to by their root; for instance, a major triad with an additional major seventh is simply known as Cmaj7.
Due to their dissonant nature, seventh chords can be more challenging for voice leaders to navigate than triads. When playing these chords with a melody line or melody loops, playing directionally becomes essential; most commonly heard is a falling fifth root motion where an E7 chord’s root resolves up to an A or D via voice leading. In many instances this method proves most successful at resolving seventh chords.
Major Seventh Chords
This chapter introduces us to major seventh chords, which can be found both contemporary music and romantic songs such as Claude Debussy’s “Claire de Lune.” They have a warm sound which adds emotion and brings depth to any song.
A seventh chord is a four-note chord composed of a triad and the seventh scale degree (either unmodified (natural) or modified by half steps to flatten out, often called the seventh scale degree). Seven-note chords can be created in all keys; their qualities depend on which type of triad and seventh it comprises.
Music theory typically classifies seventh chords according to their triad and seventh content as well as any inversion (which will be discussed further in Chapter 11: Inversions and Figured Bass). A chord with major triad and major seventh above it is known as a major-major seventh chord.
Minor Seventh Chords
Like triads, seventh chords can be written both melodically and harmonically. To write a minor seventh chord on a staff, draw its root note onto it before adding notes stacked in thirds above (imagine drawing an extra-long snowperson).
Note that intervals used in a seventh chord must correspond with its scale of origin – for instance, two and five of a major seventh chord must use minor intervals and vice versa.
There are two seventh chord qualities based on diminished triads: half-diminished and fully-diminished. Both include a diminished triad with a minor seventh; those created on me or le feature both major and diminished sevenths while ti includes both minor and diminished sevenths.
Similar to major seventh chords, minor seventh chords require resolution by way of either falling-fifth or rising-fourth root motion – you can hear this effect in the opening notes from West Side Story’s song “Somewhere.”
Dominant Seventh Chords
Dominant seventh chords generate an air of tension in music. Their distinctive dissonance results from having an interval containing three scale degrees between their third scale degree and flat seventh scale degree; therefore, dominant sevenths are always flat when placed adjacent to a key’s tonic chord.
The dominant seventh chord is one of the most frequently occurring seventh chords in Western art music and often known simply as V7 chord.
When not otherwise specified, seventh chords are assumed to be dominant seventh chords.
A seventh chord can be defined as any triad containing an extra note that creates an interval of one seventh above its root chord. There are four types of seventh chords; each type has its own distinctive sound that fits well within different musical genres.