Music theory > Lessons > Pitch of sounds > Intervals > Doubly augmented fourth

Doubly augmented fourth

In music theory, a doubly augmented fourth is an interval that has seven half steps (semitones). Explanations and excerpts from famous works

In music theory, a doubly augmented fourth is an interval that has seven half steps (semitones ).

The doubly augmented fourth requires that:

The interval must be a fourth interval (four note names between the first and the last).
The interval must have seven half steps.

What does a doubly augmented fourth look like?

Here is an example of a melodic doubly augmented fourth (two music notes in a melody) and a harmonic doubly augmented fourth (in a chord):

How to recognize a doubly augmented fourth?

Rule of music theory: All intervals in a major scale starting with the tonic (degree I) are either major or perfect, and only unison, octave, fourth and fifth are perfect (the others are major).

Example with the interval A♭ / D♯ :

Let's take the A flat major scale to have A♭ as the tonic:

From the rule stated above, the interval A♭ / D♭ is a perfect fourth, so the interval A♭ / D♮ is an augmented fourth, and so the interval A♭ / D♯ is a doubly augmented fourth.