A seventh chord contains four notes and adds an eighth interval above the root note of a triad. They have an unpleasant dissonant sound that creates tension and movement in music.
Seventh chords come with more quality types than triads; for theory lessons we will focus on just six of them.
Addition of the seventh chord can add depth and emotion to any triad chord, making it suitable for genres such as Jazz, R & B and Blues as well as many pop chord progressions.
Sevenths chords are composed of scale degrees 1 through 3, 5 through 7, arranged so as to form four qualities depending on how they’re constructed and the interval relationships among their notes.
To create a major seventh chord, it’s essential to first identify its root note on the staff. One way is by drawing an extra-long snowperson above it and noting any accidentals from its key signature.
Once the root is identified, add any notes a third above it and a seventh above that to create chords of different qualities. Examine how each note connects with its neighboring notes as part of your chord construction process.
Minor seventh chords consist of three notes in unison with an added minor seventh added on top. This seventh may be natural (no sharps or flats) or diminished; diminished sevenths are generally the more popular choice.
Seventh chords can be built at any scale degree, though they are less frequent in tonal music than major sevenths. When they do appear, they usually resolve by falling-fifth or rising-fourth motion to sonorities that lie five steps below or above its own root note.
As with triads, the identity of a seventh chord is determined by its quality; that is determined by its triad and seventh intervals. Identification can be performed easily in closed spacing without doubled notes: simply imagine or write out its root and its third, fifth and seventh to identify it. Open spacing becomes more challenging where doubled notes are used but this process still can be accomplished by writing out its key signature before adding accidentals (as illustrated below) – as can any quality.
Half-diminished seventh chords can be thought of as regular diminished chords with an added flattened seventh, typically seen on diatonic II chords in minor modes and functioning either as dominant tonic or secondary dominant chords – such as those found in Garth Brooks’ song Friends in Low Places which features such progression.
This type of chord is also known as a minor 7 flat 5 chord and its formula is 1 – 3 – 5 – 7. These chords are commonly found as the first chord in jazz standards where minor chords such as II, V or I may appear.
The note interval qualities include diminished, minor, major, perfect and augmented notes. Each chord in a piano diagram has its own note interval quality represented by color on the piano diagram; also named by its starting point from which sharp or flat accidentals may be added to major scale notes above it.
Dominant seventh chords are an integral component of blues music. While they can be quite dissonant and draw your ears back toward the tonic chord (chord root), they’re still extremely popular and should never be underestimated when used correctly.
To create a dominant seventh, begin by stacking two thirds on top of a major triad and evaluating each note’s interval relationship to ascertain its chord quality.
Each chord type possesses its own note interval quality – diminished, minor, major, perfect and augmented – depending on which scale degree notes it utilizes when creating its triads.
This table lists note interval qualities with their short abbreviations/note names to help you select chord qualities for any given key. It will show which note intervals can be used to build your triads, and where flat/sharp accidentals need to be applied.