Basic Music (TC 12-41/ NAVEDTRA 01244) describes the construction and interval relationships of a dominant seventh chord. In Harmony, the dominant seventh chord refers specifically to the diatonic chord which appears on the dominant scale degree. In minor the chord is borrowed from its parallel major just as is the dominant triad.

TRITONE RESOLUTION
An interval of a tritone appears between the third and seventh (leading tone and subdominant scale degrees) of the dominant seventh chord. Dissonant harmonic intervals such as the tritone of the dominant seventh chord require specific resolution. A regular resolution occurs when the third (leading tone) resolves up to the root of the tonic chord and the seventh (subdominant) resolves down to the third of the tonic chord. This is the most common resolution and satisfies the melody pull of the tendency tones.

FIGURE 7.1: Regular Resolution
When the seventh of a dominant seventh chord appears in an upper voice and the chord progresses to a first inversion tonic chord, an Irregular Resolution must occur. The Bass voice has taken the note of resolution (third of the tonic chord) and the seventh in the upper voice will rise to the fifth of the tonic chord. This will often produce harmonic intervals of a diminished fifth followed by a perfect fifth. This is called Unequal Fifths and is acceptable under such circumstances.

FIGURE 7.2: Irregular Resolution
APPROACHING THE SEVENTH

No new guidelines are required for approaching a dominant seventh chord except for the melodic approach to the seventh. The seventh of the dominant seventh chord is considered a dissonance and should not be approached by disjunct motion from above. This is a carry-over from 16th century contrapuntal technique, which required that no accented dissonance be approached in such a manner.

FIGURE 7.3: Approaching the Seventh