In music theory, a doubly diminished sixth is an interval that has six half steps 
The doubly diminished sixth requires that:
- The interval must be a sixth interval (six note names between the first and the last).
- The interval must have six half steps.
What does a doubly diminished sixth look like?
Here is an example of a melodic doubly diminished sixth (two music notes in a melody) and a harmonic doubly diminished sixth (in a chord):
How to recognize a doubly diminished sixth?
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 B / G♭♭:
Let's take the B major scale to have B as the tonic:
From the rule stated above, the interval B / G# is a major sixth, so the interval B / G♮ is a minor sixth, so the interval B / G♭ is a diminished sixth, and so the interval B / G♭♭ is a doubly diminished sixth.
Inversion of the doubly diminished sixth
The inversion of the doubly diminished sixth is the doubly augmented third.
Here is an example of a doubly augmented third:
Musical examples of doubly diminished sixth
No examples yet, but feel free to send me some examples!
Interval identification game
You will find this interval in my Intervals identification game:
