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.
Major Seventh
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
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
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
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.
Seventh chords add a distinct sound and more movement and dissonance than their triad counterparts, creating a fuller sound in music compositions. Learning these shapes is an excellent way to make songs sound fuller and more dynamic.
To create a seventh chord, draw its root note on the staff and add notes representing its third, fifth, and seventh in succession (like building an extra-long snowperson). Don’t forget any accidentals in your key signature!
Dominant 7th
The dominant 7th chord was among the first regularly appearing seventh chords in Western art music, making an impactful and versatile statement about its composer’s imagination and musical taste. Simply defined, a dominant seventh is defined as any major chord with a flattened seventh; this creates an interval which falls half step lower than its respective key’s seventh note, creating an entirely distinct sound from that of major chords.
To create a dominant seventh chord, start with a major triad and add the flattened seventh. This creates a powerful and dissonant chord ideal for creating tension – it is frequently employed in rock, blues, and jazz music where it typically forms part of V-I progressions that resolve back to tonic notes.
The dominant seventh is an ideal way to create cadences due to its natural resolution of falling-fifth root motion toward tonic in many standard chord progressions. It is frequently employed as the root note in classical music or as the leading note in modal music where it helps progress toward mediant and subdominant chords.
As with minor and major seventh chords, dominant sevenths can also be altered to create an even stronger and tenser sound. This technique is especially popular in jazz where it is frequently enhanced with an additional flattened fifth – creating an A7b9 chord with additional dissonance that adds tension for a stronger feel.
While jazz musicians frequently employ the augmented seventh chord as a replacement for dominant seventh, it can also stand alone as an independent chord. Constructed by adding a minor seventh to a diminished triad, its sound provides similar dissonant qualities as dominant seventh yet has more dramatic and intense tones. Furthermore, this chord can help create cadences, as it often appears in chromatic music.
Diminished 7th
The diminished 7th chord stands out among seventh chords for two reasons. First, its structure is symmetrical – all intervals from 1 to b3, b5 to b7, and b3 to b5 are at equal distances (a minor third). This makes it simple and straightforward to remember without needing to pay attention to which notes will be flat or sharp like most other chords require.
Second, seventh chords can be built upon any one of three scale degrees from their leading tone, making them versatile chords that work in any key. Though less popular among popular composers than other seventh chords, knowing them may provide effective transitions into unusual or unfamiliar chords and keys.
Due to having four notes, diminished 7th chord analysis can be more complex than simple triad analysis; however, using our previously developed method we can still reduce it to its essence using this four-note structure. Much like major and minor triads, diminished 7ths have various quality types depending on which scale degrees are modified; for our purposes however we’ll only focus on its basic form with its leading tone as its anchor point.
Diminished chords tend to be dissonant and are therefore best used sparingly as part of a musical phrase before transitioning onto another chord.
This can be achieved most frequently by switching from dim7 to dom7; however, an alternative approach would be dropping one semitone from dim7’s final note and creating a rootless secondary dominant seventh chord.
As part of an analysis of a diminished seventh chord, it’s crucial that careful consideration be given to accidentals. Seventh chords tend to be less stable than their triadic counterparts, so any time we move away from root position further from root position more instability results. Therefore it is essential that inversions and figured bass be used in order to maintain melodic sounding chords that sound stable and melodic.