interval
G♯ diminished fifth
G♯lowerDupperd56 half steps
A perfect fifth narrowed by a half step. The interval inside every diminished triad.
On the keyboard
What is true of it
G♯ up a diminished fifth is D: 6 half steps, and 5 letters counting both ends.
Turn it upside down — put the G♯ on top — and it becomes a augmented fourth. The two numbers always add to nine, and the two sizes to twelve.
It is a dissonance.
Six half steps can be written two ways: G♯ to C𝄪 is a fourth, G♯ to D is a fifth. They sound the same and behave differently.
Every interval on G♯
G♯ → Aminor second · dissonanceG♯ → A♯major second · dissonanceG♯ → Bminor third · imperfect consonanceG♯ → B♯major third · imperfect consonanceG♯ → C♯perfect fourth · perfect consonanceG♯ → C𝄪augmented fourth · dissonanceG♯ → D♯perfect fifth · perfect consonanceG♯ → Eminor sixth · imperfect consonanceG♯ → E♯major sixth · imperfect consonanceG♯ → F♯minor seventh · dissonanceG♯ → F𝄪major seventh · dissonance