Strengthening Endings with V7
Adding a seventh to the dominant triad produces V⁷ — a chord of four distinct pitches that intensifies the pull toward the tonic. The seventh (4̂, fa) is a dissonance that must resolve by falling by step to the third of the tonic chord (3̂, mi). Combined with the leading-tone (7̂, ti) resolving upward to 1̂ (do), V⁷ creates two simultaneous voice-leading tendencies pressing toward I, making it considerably more urgent than a plain V triad.
In four-voice writing (SATB), one pitch of V⁷ is typically doubled — usually the root — while the seventh and leading tone retain their obligatory resolutions. When V⁷ resolves to I, the tonic chord is nearly always complete. Compare this to plain V–I, where the leading tone in an inner voice may occasionally leap down to the fifth of I: the seventh of V⁷ removes that flexibility by adding its own mandatory descent, so voice leading becomes more constrained and directional.
V⁷ can appear in root position or in any inversion. In root position (V⁷), the bass leaps from 5̂ to 1̂ — an especially decisive motion at a perfect authentic cadence. The inversions (V⁶₅, V⁴₃, V⁴₂) are discussed separately in the context of tonic prolongation, where they smooth out bass lines rather than mark cadences. At phrase endings, root-position V⁷ followed by root-position I is the gold standard for harmonic strength and finality.
