Seventh chords are an integral component of many styles of music, providing tension and resolution in their progression while having their own distinct sound.
To create a seventh chord, start by building a basic triad. Next, layer another third and assess their relationship to one another to ascertain its quality.
Major
No matter your experience level in music, chances are you have come across chords with 7’s in their names before. These chords are known as major seventh chords and created by adding one major seventh degree lowered one half step to any triad or chord in order to produce them.
Just like triads, seventh chords can also be stacked to fill all lines and spaces of a staff. When used this way, seventh chords typically consist of one bottom note, two middle notes, and a head note that are written melodically and harmonically. Their qualities are often named according to both their triad type and seventh quality – with some common seventh chord types including these:
Minor
Minor seventh chords tend to sound darker and more melancholic than major ones due to flat seventh intervals that dissonantly clash with perfect ones in minor triads.
To identify a minor seventh chord, draw its root on the staff and write in its accidentals from your key signature for its third and fifth notes above its root.
Note that the sixth and seventh of a triad should fall one whole step below their octave above the root; these intervals help determine the quality of a chord; thus do and fa chords have major triads with minor sevenths while sol and ti chords feature diminished triads with minor sevenths.
Dominant
Dominant seventh chords can be found throughout popular music. From blues progressions, funk music, and bebop. Dominant seventh chords play an essential part in harmonic function as they help resolve other chords by creating tension that drives progression forward.
A dominant seventh chord consists of a major triad and minor seventh positioned above its root; when these elements are in root position, this chord is commonly known as a Cmaj7 chord.
When used in another position, a dominant seventh can be called a 7alt or dominant 9 (or 7th). This chord can also be altered by adding #9, 13, or other crunchy notes; you can identify these chords using their “just a number” symbols on fake sheets and sheet music; examples would be 7(b9) or 7(13).
Half-diminished
A half-minished seventh chord creates tension that needs to be released through another chord, such as its complement or resolution by another note.
A seventh chord’s note quality is determined by its type of triad and seventh interval above its root, as well as if both elements belong to the same type – these would then be known as major-major or minor-minor chords, respectively.
When the triad and seventh chord are of different types, then it is known as a diminished seventh or augmented sixth chord. Most textbooks refer to seventh chords by their type name so it is essential that you learn both before exploring their various characteristics.
Whole-diminished
The whole diminished scale – which contains the same intervals as a minor seventh flat five chord with two notes flattened – can be challenging to learn due to its mixture of whole tones and semitones; depending on your starting point, its distances between pitches may shift upward or downward by either one whole tone or half step.
Diminished seventh chords can be an effective tool in music to generate tension or disquiet, unlike major or minor chords which fit within an established harmonic progression and thus create drama and intrigue. They add another emotional depth to pieces by conveying anger, sadness or pain effectively.