interval
A♭ minor second
A♭lowerB♭♭upperm21 half steps
One half step, written as a second: the smallest distance between two notes with different letters.
On the keyboard
What is true of it
A♭ up a minor second is B♭♭: 1 half step, and 2 letters counting both ends.
Turn it upside down — put the A♭ on top — and it becomes a major seventh. The two numbers always add to nine, and the two sizes to twelve.
It is a dissonance.
Every interval on A♭
A♭ → B♭major second · dissonanceA♭ → C♭minor third · imperfect consonanceA♭ → Cmajor third · imperfect consonanceA♭ → D♭perfect fourth · perfect consonanceA♭ → Daugmented fourth · dissonanceA♭ → E♭♭diminished fifth · dissonanceA♭ → E♭perfect fifth · perfect consonanceA♭ → F♭minor sixth · imperfect consonanceA♭ → Fmajor sixth · imperfect consonanceA♭ → G♭minor seventh · dissonanceA♭ → Gmajor seventh · dissonance