# Intervals

An interval is the inclusive distance between two music notes. An interval can be **melodic** or **harmonic**.

Each melodic or harmonic interval has a **number** and a **quality**, we will see this later.

## Melodic interval

A melodic interval is an interval in a melody when notes are played one after the other:

## Harmonic interval

An harmonic interval is an interval between two notes in the same chord, when notes are been playing at the same time:

## Melodic motions

Melodic motions can be conjunct or disjunct:### Conjunct melodic motion

When 2 notes follow each other, then it is a conjunct melodic motion:

(Conjunct melodic motions can be ascending or descending)

### Disjunct melodic motions

When 2 notes do not follow each other, then it is a disjunct melodic motion:

(Disjunct melodic motions can be ascending or descending)

## Number of an interval

Each interval has a **number** that is the number of letter name it contains.

### List of interval numbers

- 1
**Unison** - 2
**Second** - 3
**Third** - 4
**Fourth** - 5
**Fifth** - 6
**Sixth** - 7
**Seventh** - 8
**Octave** - 9
**Ninth** - 10
**Tenth** - 11
**Eleventh** - 12
**Twelfth** - 13
**Thirteenth** - and so on

For example, if you consider the interval starting from C and ending on G, you must count like this: C-D-E-F-G = 1-2-3-4-5, so this interval is a fifth (5th).

The unison is a null interval, that is to say that the 2 music notes of a unison intervall have the same sound.

## Ascending and descending intervals

An interval can be ascending or descending:

## Interval quality

To identify intervals with precision, intervals have a quality identifier.

Qualities of intervals can be one of them:

**Perfect****Major****Minor****Augmented****Diminished****Doubly diminished****Doubly augmented**

But all intervals can't be identified with some of all identifiers, here are all possibilities:

Major | Minor | Perfect | Augmented | Diminished | Doubly augmented | Doubly diminished | |

Unison | |||||||

Second | |||||||

Third | |||||||

Fourth | |||||||

Fifth | |||||||

Sixth | |||||||

Seventh | |||||||

Octave |

Below is the same table but classified to be more clear:

Major | Minor | Perfect | Augmented | Diminished | Doubly augmented | Doubly diminished | |

Unison | |||||||

Octave | |||||||

Fourth | |||||||

Fifth | |||||||

Second | |||||||

Third | |||||||

Sixth | |||||||

Seventh |

Only **unisons**, **fourths**, **fifths** and **octaves** can be __perfects__ but never *major* or *minor*.

Only **seconds**, **thirds**, **sixths** and **sevenths** can be __major__ or __minor__ but never *perfects*.

## Intervals qualities in the C Major scale

Starting from the first note of the C Major scale, all intervals are only **Majors** or **Perfects**

C - C | Unison | Perfect |

C - D | Second | Major |

C - E | Third | Major |

C - F | Fourth | Perfect |

C - G | Fifth | Perfect |

C - A | Sixth | Major |

C - B | Seventh | Major |

C - C | Octave | Perfect |

__You should keep in mind that in all Major scales, from the first note of the Major scale, all intervals are only Majors or Perfects.__

## Augmented and diminished intervals

- When a half step (semitone ) is added to a
**major**interval, it results in an**augmented**interval - When a half step is removed to a
**major**interval, it results in a**diminished**interval

- When a half step is added to a
**perfect**interval, it results in an**augmented**interval - When a half step is removed to a
**perfect**interval, it results in a**diminished**interval

- When a half step is added to an
**augmented**interval, it results in a**doubly augmented**interval - When a half step is removed to a
**diminished**interval, it results in a**doubly diminished**interval

## Examples of augmented and diminished intervals

## Examples of minors, majors, augmented and diminished intervals

## How to find interval name and quality?

For example, let's consider the interval C - B♭ :

C D E F G A B = 1 2 3 4 5 6 7 = Seventh

The name of the interval C - B♭ is Seventh.

Now we will find the quality of this interval:

We know that from the first note of the C Major scale, all intervals are only Majors or Perfects and that only seconds, thirds, sixths and **sevenths** can be majors or minors but never perfects...

So the interval C - B♮ is a seventh major, **so the interval C - B♭ is a seventh minor**!

That's all! Easy no?

## Numbers of whole steps (tones) in intervals

List of intervals according to the number of whole steps (tones):

Major | Minor | Perfect | Augmented | Diminished | Doubly augmented | Doubly diminished | |

Unison | 0 | ||||||

Second | 1 | 0.5 | 1.5 | 2 | |||

Third | 2 | 1.5 | 2.5 | 1 | 3 | 0.5 | |

Fourth | 2.5 | 3 | 2 | 3.5 | 1.5 | ||

Fifth | 3.5 | 4 | 3 | 4.5 | 2.5 | ||

Sixth | 4.5 | 4 | 5 | 3.5 | 5.5 | 3 | |

Seventh | 5.5 | 5 | 6 | 4.5 | 6.5 | 4 | |

Octave | 6 |

## Enharmonic

Two notes are **enharmonic** when they are tuning the same pitch, but spelled or named differently, examples:

## Inversion of intervals

An interval can be inverted by raising the lower pitch an octave or lowering the upper pitch an octave, example:

**unison** become **octave**

**second** become **seventh**

**third** become **sixth**

**fourth** become **fifth**

**fifth** become **fourth**

**sixth** become **third**

**seventh** become **second**

**octave** become **unison**

During inversions, intervals qualities change like this:

- **Diminished** intervals become **augmented**

- **Minors** intervals become **majors**

- **Majors** intervals become **minors**

- **Augmented** intervals become **diminished**

- **Perfects** intervals stay **perfects**

## Compound intervals

A compound interval is an interval greater than one octave:

The quality of a compound interval is the same as the corresponding simple interval.

## Intervals in the chromatic scale

Each notes of the chromatic scale are separated by a harf step interval (semitone), which can be either diatonic or chromatic:

Here is the ascending chromatic scale played on the piano:

And the descending chromatic scale:

Reminder :

- A half step is chromatic when the two notes have the same name (C / C♯)

- A half step is diatonic when the two notes do not have the same name (C / D♭)

## Liste of intervals

- Perfect unison
- Major second
- Minor second
- Augmented second
- Doubly augmented second
- Major third
- Minor third
- Augmented third
- Diminished third
- Doubly augmented third
- Doubly diminished third
- Perfect fourth
- Augmented fourth
- Diminished fourth
- Doubly augmented fourth
- Doubly diminished fourth
- Perfect fifth
- Augmented fifth
- Diminished fifth
- Doubly augmented fifth
- Doubly diminished fifth
- Major sixth
- Minor sixth
- Augmented sixth
- Diminished sixth
- Doubly augmented sixth
- Doubly diminished sixth
- Major seventh
- Minor seventh
- Augmented seventh
- Diminished seventh
- Doubly augmented seventh
- Doubly diminished seventh
- Perfect octave

External links to learn more about :

1 - https://www.dolmetsch.com/musictheory12.htm

2 - https://en.wikipedia.org/wiki/Interval_(music)