Discussion 3b - Seventh Chords

Class Discussion

The purpose of inversion figures is purely a shorthand to identify what note is in the bass.

Lowest pitch=bass. The root of the chord is the identifying factore of the chord, where thirds are stacked around. These thirds can take different forms as a chord becomes inverted.

How do we determine seventh chord quality?

The first letter gives the quality of the triad, while the second letter gives the quality of the seventh. For example, Mm7 = a major triad + a minor seventh.

Looking at both the triads in the seventh chord and be aware of the different qualities they have.

Dominant and Dimished relationship: They both have diminished 5ths. Dominant is between 3rd and 7th, while diminished is 1st and 5th (all chordal pitches).

The five seventh chords we use are: -Major Seventh(MM) - (Major Major) - (Do,Mi,So,Ti) -Dominent Seventh(Mm) - (Major Minor) - (So,Ti,Re,Fa) -Minor Seventh(mm) - (Minor Minor) - (La,Do,Mi,So) -Half-Diminished Seventh(dm) - (Diminished Minor) - (Ti,Re,Fa,La) -Fully-Diminshed Seventh(dd) - (Diminished Diminished) - (Ti,Re,Fa,LEY)

The colloquial names for these chords are first(Dominent Seventh), followed by the shorthand used in identifying the chords(Mm), then the name we will use in this theory class to label these chords (Major Minor) The solfege provided correspond to where we find these 7th chords in diatonic major scales (So,Ti,Re,Fa), save for the Fully-Diminished chord that occurs in minor.

How do we determine and label seventh chord inversions?

Seventh chords add third inversion because they have an additional note compared to triads. Their inversion figures are as such:

• Root position: 7 (Root in the Bass)
• First inversion: 6/5 (Third in the Bass)
• Second inversion: 4/3 (Fifth in the Bass)
• Third inversion: 4/2 (Seventh in the Bass)

Remember to not add the slash when handwriting. Stacked things are just impossible to notate online.

The inversions figures do not tell you the exact intervals and their qualities above the bass. These are made to work with roman numberals.

Further Reading

From Open Music Theory

Seventh chords

A four-note chord whose pitch classes can be arranged as thirds is called a seventh chord.

Like with a triad, the pitch classes belonging to a seventh chord occupy adjacent positions (a four-pitch-class clump) on the circle of thirds. The four members of a seventh chord are the root, third, fifth, and seventh.

There are five qualities of seventh chords that appear in diatonic music: major seventh, dominant seventh, minor seventh, diminished seventh (also called fully-diminished), and half-diminished seventh. They are comprised of the following intervals above their roots:

• major seventh: M3, P5, and M7 above the root (or major triad with a major seventh)
• dominant seventh: M3, P5, and m7 above the root (or major triad with a minor seventh)
• minor seventh: m3, P5, and m7 above the root (or minor triad with a minor seventh)
• diminished seventh: m3, d5, and d7 above the root (or diminished triad with a diminished seventh)
• half-diminished seventh: m3, d5, and m7 above the root (or diminished triad with a minor seventh)

Following are the lead-sheet abbreviations for seventh-chord qualities:

• major seventh: maj7 or △7 (G^maj7 or G^△7)
• dominant seventh: 7 (B⁷)
• minor seventh: m7 (F♯^m7)
• diminished seventh: dim7 or °7 (D^dim7 or D^°7)
• half-diminished seventh: ⦰7 (A^⦰7)