Interval is just a fancy name for a two-note chord…
Welcome to a gallery of the most commonly encountered intervals–each possessing a unique degree of harmonic consonance or dissonance–and stability or instability…
Perfect Unison
A Perfect Unison (usually just called a Unison) occurs when two or more voices sing or play the exact same note in the same register. It is called perfect because it is highly consonant.
- Chord symbol: P1
- Chord structure = 1-1
- Character: perfect consonance
Minor Second
The Minor Second spans two letters (for example: C-Db) and two physical piano keys.
- Chord symbol: m2
- Chord Structure = 1-b2
- Character: extreme dissonance
Major Second
The Major Second spans two letters (for example: C-D) and three physical piano keys.
- Chord symbol: M2
- Chord structure = 1-2
- Character: Moderately Dissonant
Minor Third
The Minor Third spans three letters (for example, C-D-Eb) and four physical piano keys.
- Chord symbol: m3
- Chord structure= 1-b3
- Character: dark consonance
Major Third
The Major Third spans three letters (for example, C-D-E) and five physical piano keys.
- Chord symbol: M3
- Chord structure = 1-3
- Character: consonant and bright
Perfect Fourth
The Perfect Fourth spans four letters (for example, C-D-E-F) and six physical piano keys. It is called perfect because it is highly consonant.
- Chord symbol: P4
- Chord structure: 1-4
- Character: consonant, but unstable
Augmented Fourth
The Augmented Fourth spans four letters (for example, C-D-E-F#) and seven physical keys. It is called augmented because it is one physical key “larger” than a perfect 4th.
- Chord symbol: A4
- Chord structure: 1-#4
- Character: extremely dissonant, highly unstable, craves resolution
Note: The Augmented Fourth is also called a Tritone because it spans three whole tones. By the way, the Diminished Fifth is also a Tritone. The difference between an A4 and d5 is purely theoretical. Both intervals share the exact same physical notes but have different letter names. The naming conventions will become clear in later studies of chords and chord progressions.
Diminished Fifth
The Diminished Fifth spans five letters (for example, C-D-E-F-Gb) and seven physical piano keys. It is called diminished because it is one physical key “smaller” than a perfect 5th.
- Chord symbol: d5
- Chord structure: 1-b5
- Character: extremely dissonant, highly unstable, craves resolution.
Note: The Diminished Fifth is also called a Tritone because it spans three whole tones. By the way, the Augmented Fourth is also a Tritone. The difference between an A4 and d5 is purely theoretical. Both intervals share the exact same physical notes but have different letter names. The naming conventions will become clear in later studies of chords and chord progressions.
Perfect Fifth
The Perfect Fifth spans five letter names (for example, C-D-E-F-G) and eight physical piano keys. It is called perfect because it is highly consonant.
- Chord symbol: P5
- Chord structure: 1-5
- Character: highly consonant and stable.
Augmented Fifth
The Augmented Fifth spans five letters (for example, C-D-E-F-G#) and nine physical piano keys. It is called augmented because it is one physical key “larger” than a perfect fifth.
- Chord symbol: A5
- Chord structure: 1-#5
- Character: moderately dissonant, dreamy.
Minor Sixth
The Minor Sixth spans six letters (for example, C-D-E-F-G-Ab) and nine physical piano keys.
- Chord symbol: C6
- Chord structure: 1-b6
- Character: consonant, mildy unstable.
Major Sixth
The Major Sixth span six letters (for example, C-D-E-F-G-A) and ten physical piano keys.
- Chord symbol: M6
- Chord structure: 1-6
- Character: consonant, mildly unstable.
Minor Seventh
The Minor Seventh spans seven letter names (for example, C-D-E-F-G-A-Bb) and eleven physical piano keys.
- Chord symbol: m7
- Chord structure: 1-b7
- Character: dissonant, unstable.
Major Seventh
The Major Seventh spans seven letter names (for example, C-D-E-F-G-A-B) and twelve physical piano keys.
- Chord symbol: M7
- Chord structure: 1-7
- Character: dissonant, unstable.
Perfect Octave
The Perfect Octave (usually just called an Octave) spans eight letter names (C-D-E-F-G-A-B-C) and thirteen physical pain keys. It is called an Octave because it span eights letter names and perfect because it is highly consonant and is harmonically equivalent to a perfect unison.
- Chord symbol: P8
- Chord structure: 1-8
- Character: extremely consonant and stable.
Intervals Larger than an Octave
Intervals larger than an octave, sometimes called compound intervals, are commonly used to describe chord structures that theoretically span beyond one octave (for example: 9ths, 10ths, 11ths, 13ths). But don’t worry about compound intervals for the moment. We will have plenty of exposure and when we study chord structure and specific examples commonly used in jazz harmony.