Introduction
An interval is the distance in pitch between two notes. The smallest interval is a semitone. This is the distance between, for example, C and C#.
An interval is the relationship between two separate musical pitches. For example, in the melody “Twinkle Twinkle Little Star,” the first two notes (the first “twinkle”) and the second two notes (the second “twinkle”) are at the interval of one fifth. What this means is that if the first two notes were the pitch C, the second two notes would be the pitch “G”—four scale notes, or seven chromatic notes (a perfect fifth), above it.
Listen: Intervals
Please listen to the following audio file to hear the intervals in “Twinkle Twinkle Little Star”
Common Intervals
The following are common intervals:
| Root | Major third | Minor third | Fifth |
|---|---|---|---|
| C | E | E♭ | G |
| D♭ | F | F♭ | A♭ |
| D | F♯ | F | A |
| E♭ | G | G♭ | B♭ |
| E | G♯ | G | B |
| F | A | A♭ | C |
| F♯ | A♯ | A | C♯ |
| G | B | B♭ | D |
| A♭ | C | C♭ | E♭ |
| A | C♯ | C | E |
| B♭ | D | D♭ | F |
| B | D♯ | D | F♯ |
Compound Intervals
In the musical scale, there are twelve pitches; the names A, B, C, D, E, F, and G. When the intervals surpass the perfect Octave (12 semitones), these intervals are called compound intervals, which include particularly the 9th, 11th, and 13th intervals—widely used in jazz and blues music.
Compound intervals are formed and named as follows:
- 2nd + Octave = 9th
- 3rd + octave = 10th
- 4th + Octave = 11th
- 5th + octave = 12th
- 6th + Octave = 13th
- 7th + octave = 14th
Consonant and Dissonant Intervals
Consonance in music, is when a combination of notes sounds pleasant. Examples of consonant intervals is music played in unison, major and minor thirds, perfect fourths and fifths, major and minor sixths, and octaves.
Dissonance is a combination of notes that sound unpleasant or harsh. Dissonant interval examples are major and minor seconds, tritone, and major and minor sevenths.
The consonant intervals are considered the perfect unison, octave, fifth, fourth and major and minor third and sixth, and their compound forms. An interval is referred to as “perfect” when the harmonic relationship is found in the natural overtone series (namely, the unison 1:1, octave 2:1, fifth 3:2, and fourth 4:3). The other basic intervals (second, third, sixth, and seventh) are called “imperfect” because the harmonic relationships are not found mathematically exact in the overtone series. In classical music the perfect fourth above the bass may be considered dissonant when its function is contrapuntal.
Other intervals, the second and the seventh (and their compound forms) are considered dissonant and require resolution (of the produced tension) and usually preparation (depending on the music style used). It should be noted that the effect of dissonance is perceived relatively within musical context: for example, a major seventh interval alone (i.e. C up to B) may be perceived as dissonant, but the same interval as part of a major seventh chord may sound relatively consonant. A tritone (the interval of the fourth step to the seventh step of the major scale, i.e. F to B) sounds very dissonant alone, but less so within the context of a dominant seventh chord (G7 or D♭7 in that example).
Theory Lesson: Intervals
Please click on the following link to participate in an interactive lesson on intervals: Specific Intervals. To start the lesson, click on the play button.