Consonance
A stable, harmonious relationship between multiple notes
Consonance is the quality of two or more notes sounding stable, pleasant, and resolved together — the opposite of dissonance. The more closely two notes are related in the harmonic series, the more consonant they sound. This is the point where mathematics meets music.
The most consonant intervals, in order, with their semitone count and the ratio between their frequencies:
- unison (the same note twice, 1:1)
- octave (12 semitones, 2:1)
- perfect 5th (7 semitones, 3:2)
- perfect 4th (5 semitones, 4:3)
- major 3rd (4 semitones, 5:4)
- minor 3rd (3 semitones, 6:5)
The major triad is the most consonant chord, built entirely from the first five harmonics and so present in every resonant sound. The minor triad, also built from the first five harmonics, is next. Consonant sounds are stable, and that stability makes them the resting base of music.
Across the graph, each noteset carries a rough consonance score from 1 to 10, judged relative to its siblings: intervals against intervals, chords (triads and tetrads together) against chords, scales against scales. The number reflects how consonant something is among its peers, so a chord scored 5 is more consonant than an interval scored 5. It is paired with commonality, which measures how often a noteset is used rather than how stable it sounds. The two usually agree but diverge tellingly for tense yet ubiquitous sounds like the tritone and the dominant 7th.