Dissonance
A tense, unstable relationship between multiple notes
Dissonance is the quality of two or more notes sounding tense, clashing, and unresolved together — the opposite of consonance. Dissonant intervals create energy that wants to move, to return to consonance. Yet dissonance is essential: music without it would have no tension, no surprise, and no forward motion.
The most dissonant intervals, in order, with their semitone count and the ratio between their frequencies:
- minor 2nd (1 semitone, 16:15)
- major 7th (11 semitones, 17:9)
- major 2nd (2 semitones, 9:8)
- minor 7th (10 semitones, 16:9)
The tritone (6 semitones, 45:32) is a special case, known traditionally as the devil's interval. Its ratio is acoustically complex, and it sounds especially jarring where the ear expects the consonant intervals around it, the perfect 4th and perfect 5th. Chords built on these dissonant intervals are used sparingly and deliberately, so the listener is not left waiting too long for resolution.