Musical intervals
Every interval from the unison to the octave: its size in semitones, its frequency ratio and cents, how it sounds, how to recognise it by ear, and how it inverts. Each one is playable and spelled on every note.
Perfect unisonThe perfect unison is two notes at the same pitch, with zero semitones and a ratio of 1:1, and it is the baseline for measuring every other interval.0 semitones · C to CMinor secondThe minor second spans one semitone with a just ratio of 16:15, the narrowest step used in Western tonal music.1 semitones · C to D♭Major secondThe major second is a whole tone of two semitones, with a just ratio of 9:8, and it is the step between most neighbouring degrees of the major scale.2 semitones · C to DMinor thirdThe minor third spans three semitones with a just ratio of 6:5, the darker of the two thirds and the interval that gives minor triads their colour.3 semitones · C to E♭Major thirdThe major third spans four semitones with a just ratio of 5:4, the bright imperfect consonance that gives major chords their sound.4 semitones · C to EPerfect fourthThe perfect fourth spans five semitones with a just ratio of 4:3, an open interval whose stability depends on which note sits in the bass.5 semitones · C to FTritoneThe tritone spans six semitones with a just ratio of 45:32, a dissonance spelled as an augmented fourth or a diminished fifth.6 semitones · C to F♯Perfect fifthThe perfect fifth spans seven semitones with a just ratio of 3:2, an open, stable interval at the core of major and minor triads.7 semitones · C to GMinor sixthThe minor sixth spans eight semitones with a just ratio of 8:5, a dark imperfect consonance that inverts to the major third.8 semitones · C to A♭Major sixthThe major sixth spans nine semitones with a just ratio of 5:3, an open imperfect consonance that sounds bright and lifted.9 semitones · C to AMinor seventhThe minor seventh spans ten semitones with a just ratio of 9:5, a dissonance that sounds unresolved at the top of the dominant seventh chord.10 semitones · C to B♭Major seventhThe major seventh spans eleven semitones with a just ratio of 15:8, a sharp dissonance that the ear hears as a leading tone pulling toward the octave.11 semitones · C to BPerfect octaveThe perfect octave spans twelve semitones at the ratio 2:1, and the two notes share a name, making it the most stable interval after the unison.12 semitones · C to C
The ebook
Music Theory: the site as a book
The site's working library as a structured ebook: intervals, keys, harmony, counterpoint, rhythm, form, tuning, orchestration and the history behind them.
- 78 pages
- PDF format
- $2.87 only
- By The musics.name project