Seventh chords can add depth to your progressions. They consist of a triad and seventh interval above its root; giving them their unique flavor that ranges from comforting to bold.
Triads can also be easily converted to chord 7ths by moving one of the doubled notes up one fret – for instance from F major triads you could convert them to their Fmaj7 equivalent by moving up an Eb fret.
Major Seventh
The major seventh chord (commonly referred to as maj7) can be created by adding an extra note that is one major third above the root note of any triad. For example, in C major there is a trio consisting of C, E and G notes; to create a major seventh chord with them simply add in one major third above E (which would be B or D for open positions) by playing another C major triad and adding its equivalent major third above E as shown below.
As can be seen, the quality of a seventh chord can be determined by examining its interval relationship between each note stacked upon another and its root note. Varying this interval can produce chords with various qualities as well as movement and tension within a progression – for instance Bread’s “Baby I’m-a Want You” features an outstanding use of Gmaj7 chord that creates a warm yet welcoming sound to create a mellifluous feel.
Minor Seventh
Minor seventh chords add a sophisticated, contemplative quality to any chord progression and can often be found across all musical genres. They are frequently included as an addition in chord progressions.
On guitar, a minor seventh chord consists of its root note plus minor third, perfect fifth, and minor seventh notes (1, 3, 5, 7). These chords may also be known as minor seven flat five chords or half-diminished chords because they contain only minor seventh notes without the major seventh component.
CAGED chords consist of four open voicings, one re-positioning and three drop 2 voicings for open positions on the fretboard, as depicted below in diagram form with roots colored black; first inversion shown in blues and second inversion in greens respectively; each chord can then be re-positioned for lower notes on fourth, fifth or sixth string for playability.
Dominant Seventh
Dominant seventh chords are some of the most frequent guitar chords found in songs, particularly blues music. From there they get their name.
Dominant sevenths use the same intervals as major triads – root, major third, and perfect fifth – but with one full step less from octave as its seventh note (flattened 7th note). This creates a sound which falls somewhere between minor chords and major chords for an impressively powerful sound that’s sure to turn heads.
Like other diatonic chords we have discussed, the dominant seventh can also be inverted. Simply move its top note up an octave until it sits above the root note for this process to occur.
Dominant seventh chords may also be enhanced by adding either a flat or sharp 9th note – this effect can be indicated by adding an accented 7 followed by +9 or -9 to represent this modification.
Mixolydian Seventh
An effective way of grasping modal harmony can be finding major and minor licks together and then dropping one seventh note (the minor seventh). This gives an immediate taste of Mixolydian.
An effective practice exercise is to correlate each scale degree with a chord, then drone its modal chord (built from that scale). This helps identify which intervals make up each chord; for instance, C7 chord in Mixolydian contains F-C as its dominant interval.
Be wary of making the mistake of ascribing a mode to its parent scale; for instance, it can be tempting to think “F7 mixo is Bb major scale”, when that would not be accurate! Great musicians know every scale and chord individually which helps explain why their sound so potency; this applies to any harmonic structure in music!