Questions: Tritone Resolution Direction and Voice-Leading

Question 1

In C major, the tritone B–F within a G7 chord resolves to C major (I). What interval do B and F move to, and in which directions?

• A. B and F both move inward, both descending to form a unison on C
• B. B moves up a half step to C, and F moves down a half step to E — contrary motion, resolving the diminished fifth to a major third
• C. B moves down a half step to B♭, and F stays, since it is already the tonic's third
• D. B and F both expand outward — B down to A and F up to G — to form a fifth

Answer: (B)

The tritone B–F in G7 is spelled as a diminished fifth (B on bottom, F on top). Diminished fifths contract inward by half step: B moves up to C (the leading tone resolves to tonic) and F moves down to E (the fourth scale degree resolves to the third). The result is a major third C–E. This contrary motion — both voices moving toward each other — is the voice-leading mechanism that makes the V–I cadence feel inevitable. The leading tone's upward pull and the fourth degree's downward pull are each driven by half-step gravity.

Question 2

Which factor determines whether a tritone resolves by expanding outward or contracting inward?

• A. Whether the tritone is between two white keys or involves an accidental
• B. Whether the tritone is spelled as an augmented fourth (expands outward) or a diminished fifth (contracts inward) — determined by which note occupies the lower position
• C. The tempo of the piece — faster passages expand outward, slower passages contract inward
• D. The instrument — string instruments expand, wind instruments contract

Answer: (B)

The same two pitches (say, B and F) can be spelled either as a diminished fifth (B below F) or an augmented fourth (F below B). Diminished fifths contract inward to a third; augmented fourths expand outward to a sixth. The direction is determined by the voice-leading context — specifically, which note is the leading tone and which is the fourth scale degree. It is the spelling and position within the key, not any acoustic feature, that determines resolution direction.

Question 3

An augmented fourth and a diminished fifth are enharmonically equivalent in equal temperament (same number of half steps) but resolve in opposite directions.

• T. True
• F. False

Answer: True

Both the augmented fourth and diminished fifth span exactly 6 half steps — they sound the same in equal temperament. But their voice-leading resolutions differ based on spelling and context. An augmented fourth (like F–B in C major, with F below) expands outward to a major sixth or fifth. A diminished fifth (like B–F with B below) contracts inward to a major third. The same two pitches, spelled differently, create different tonal functions and resolve in opposite directions — a vivid example of how tonal context, not just acoustic content, drives voice leading.

Question 4

If a composer keeps the leading tone stationary (not resolving upward) at a V–I cadence, this is considered standard voice-leading practice and has no effect on the sense of tonal resolution.

• T. True
• F. False

Answer: False

The leading tone is scale degree 7, one half step below the tonic, and has a strong conventional pull upward. Failing to resolve it at a V–I cadence creates a friction against expectation — the ear anticipates the half-step ascent and is left unsatisfied. In strict tonal voice leading, the leading tone must ascend to the tonic. When a composer deliberately holds it down, it reads as a deceptive effect or error, not neutral practice. This resolution is not arbitrary convention but reflects the natural gravitational pull of the tritone's half-step resolution structure.

Question 5

Why does the tritone in a dominant seventh chord resolve by contrary motion, and what is the connection to the leading tone?

Model answer: The dominant seventh chord contains a tritone between the leading tone (scale degree 7) and the fourth scale degree. The leading tone has natural upward pull by half step to the tonic; the fourth scale degree has natural downward pull by half step to the third. When both resolutions happen simultaneously — the leading tone ascending and the fourth descending — the two voices move toward each other (contrary motion), and the tritone resolves. The contrary motion is not an arbitrary rule but the simultaneous expression of two independent half-step gravitational pulls.

This is the physical mechanism behind harmonic closure in tonal music. The tritone in G7 (B–F in C major) packs two half-step resolutions into one interval: B wants to move up to C (leading-tone resolution) and F wants to move down to E (fourth-degree resolution). Because these movements go in opposite directions, contrary motion is the natural outcome. Understanding this means you can predict voice-leading behavior in any tonal context that contains a tritone, not just in dominant seventh chords — including diminished sevenths, leading-tone triads, and chromatic passing harmonies.