The tritone is considered the most unstable interval in Western tonal music. What makes it uniquely dissonant compared to other dissonant intervals?
AIt spans exactly six semitones, which exceeds the natural hearing range for consonance
BIt splits the octave exactly in half, lacks strong overtone alignment, and generates bidirectional resolution pressure in both voices
CIt always contains two pitches from different diatonic scales, creating a clash between key areas
DIt is the only interval that cannot appear within a major scale
The tritone's unique instability comes from multiple factors: it divides the octave symmetrically (making it harmonically ambiguous), it has poor alignment with the overtone series (neither pitch strongly reinforces the other's harmonics), and it generates strong bidirectional resolution pressure — both voices want to resolve, either inward or outward. Options C and D are false: the tritone (F–B) occurs naturally within the C major scale.
Question 2 Multiple Choice
In G major, the dominant seventh chord (D–F#–A–C) resolves to the tonic (G–B–D). What happens to the tritone (F#–C) during this resolution?
AThe tritone dissolves by both voices staying stationary as the harmony changes beneath them
BF# moves up to G and C moves down to B, so the tritone resolves inward to a third
CF# moves down to E and C moves up to D, so the tritone resolves outward to a sixth
DThe tritone resolves by the bass note D moving to G, while F# and C remain as passing tones
The tritone F#–C resolves inward: F# (the leading tone) moves up by half step to G (the tonic root), and C (the chordal seventh) moves down by half step to B (the tonic third). Both voices move by half step in contrary motion, collapsing the diminished fifth into a major third. This specific inward resolution is what makes dominant-to-tonic feel so inevitable. Option C describes the augmented fourth resolving outward, which is the opposite interval and opposite motion.
Question 3 True / False
Consonant intervals require resolution because they create harmonic tension in the listener.
TTrue
FFalse
Answer: False
It is dissonant intervals that create tension and require resolution. Consonant intervals (perfect fifths, thirds, sixths, octaves, unisons) sound stable and self-sufficient — they can end a phrase without creating a sense of incompleteness. Dissonant intervals (seconds, sevenths, the tritone) sound tense and incomplete, generating the expectation that they will move to a consonant resolution. This is the most common confusion about this topic: the label (consonant/dissonant) and the behavior (stable/needing resolution) go in opposite directions from what students often assume.
Question 4 True / False
The cycle of dissonance and resolution — tension sought and dissolved — is what gives tonal music its sense of directed motion and arrival.
TTrue
FFalse
Answer: True
Tonal music is fundamentally organized around the tension-resolution cycle. Dissonant intervals and chords create instability that drives the music forward; their resolution to consonant intervals and stable harmonies creates the sense of arrival. Without dissonance, music has nowhere to go — it remains static. Without resolution, tension accumulates without release. The interplay between the two is the mechanism behind harmonic motion, phrase structure, and the experience of a piece 'going somewhere.'
Question 5 Short Answer
Why does the dominant seventh chord create such strong urgency to resolve to the tonic? Explain the role of its specific intervals.
Think about your answer, then reveal below.
Model answer: The dominant seventh chord (e.g., G–B–D–F in C major) contains two dissonant elements that both demand resolution simultaneously: the tritone between the third and seventh (B–F), and the minor seventh interval (G–F). The tritone wants to resolve inward — B moves up to C and F moves down to E — collapsing into a third on the tonic chord. The seventh also wants to step downward by half step. These two dissonances act together, creating compound urgency that makes the dominant seventh the strongest tension chord in tonal music.
This is why the V7–I progression is the most powerful cadential motion in tonal music. A plain V chord (without the seventh) has only the leading-tone pull; adding the seventh introduces the tritone, which dramatically amplifies the urgency. The stacking of dissonances — tritone plus minor seventh — makes the dominant seventh uniquely effective as a tension generator. When both dissonances resolve together to the tonic chord, the listener experiences a double release that feels conclusive in a way that simple V–I does not.