Chords: Intervals You Gotta Know

piano-ology-chords-intervals-you-gotta-know-featured

Interval is just a fancy name for a two-note chord…

Here is a gallery of the most commonly-encountered intervals, each possessing an inherent and unique degree of harmonic consonance or dissonance… and stability or instability

piano-ology-chords-intervals-you-gotta-know-gallery-notation

While more intervals types are theoretically possible, we are going to study only those intervals that pay practical dividends in music reading, aural comprehension, chord construction, and performance.

Let’s go!


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
piano-ology-chords-intervals-you-gotta-know-perfect-unison-notation
piano-ology-chords-intervals-you-gotta-know-perfect-unison-keyboard

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
piano-ology-chords-intervals-you-gotta-know-minor-second-notation
piano-ology-chords-intervals-you-gotta-know-minor-second-keyboard

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
piano-ology-chords-intervals-you-gotta-know-major-second-notation
piano-ology-chords-intervals-you-gotta-know-major-second-keyboard

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
piano-ology-chords-intervals-you-gotta-know-minor-third-notation
piano-ology-chords-intervals-you-gotta-know-minor-third-keyboard

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.
piano-ology-chords-intervals-you-gotta-know-major-third-notation
piano-ology-chords-intervals-you-gotta-know-major-third-keyboard

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
piano-ology-chords-intervals-you-gotta-know-perfect-fourth-notation
piano-ology-chords-intervals-you-gotta-know-perfect-fourth-keyboard

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.
piano-ology-chords-intervals-you-gotta-know-augmented-fourth-notation
piano-ology-chords-intervals-you-gotta-know-augmented-fourth-keyboard

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 the notes have different letter names. This will become clear when we study chord naming conventions 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.
piano-ology-chords-intervals-you-gotta-know-diminished-fifth-notation
piano-ology-chords-intervals-you-gotta-know-diminished-fifth-keyboard

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 the notes have different letter names. This will become clear when we study chord naming conventions 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.
piano-ology-chords-intervals-you-gotta-know-perfect-fifth-notation
piano-ology-chords-intervals-you-gotta-know-perfect-fifth-keyboard

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
piano-ology-chords-intervals-you-gotta-know-augmented-fifth-notation
piano-ology-chords-intervals-you-gotta-know-augmented-fifth-keyboard

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
piano-ology-chords-intervals-you-gotta-know-minor-sixth-notation
piano-ology-chords-intervals-you-gotta-know-minor-sixth-keyboard

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
piano-ology-chords-intervals-you-gotta-know-major-sixth-notation
piano-ology-chords-intervals-you-gotta-know-major-sixth-keyboard

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
iano-ology-chords-intervals-you-gotta-know-minor-seventh-notation
piano-ology-chords-intervals-you-gotta-know-minor-seventh-keyboard

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
piano-ology-chords-intervals-you-gotta-know-major-seventh-notation
piano-ology-chords-intervals-you-gotta-know-major-seventh-keyboard

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.
piano-ology-chords-intervals-you-gotta-know-octave-notation
piano-ology-chords-intervals-you-gotta-know-octave-keyboard

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).

Here, for example, is the interval of a minor ninth…

piano-ology-chords-intervals-you-gotta-know-minor-ninth-keyboard

That’s enough about compound intervals for the moment. We will have plenty more exposure and when we study specific example commonly used in jazz harmony.

learn more… Triads You Gotta Know

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