interval
D♭ major sixth
D♭lowerB♭upperM69 half steps
Nine half steps. The minor third turned upside down.
On the keyboard
What is true of it
D♭ up a major sixth is B♭: 9 half steps, and 6 letters counting both ends.
Turn it upside down — put the D♭ on top — and it becomes a minor third. The two numbers always add to nine, and the two sizes to twelve.
It is a imperfect consonance.
Every interval on D♭
D♭ → E♭♭minor second · dissonanceD♭ → E♭major second · dissonanceD♭ → F♭minor third · imperfect consonanceD♭ → Fmajor third · imperfect consonanceD♭ → G♭perfect fourth · perfect consonanceD♭ → Gaugmented fourth · dissonanceD♭ → A♭♭diminished fifth · dissonanceD♭ → A♭perfect fifth · perfect consonanceD♭ → B♭♭minor sixth · imperfect consonanceD♭ → C♭minor seventh · dissonanceD♭ → Cmajor seventh · dissonance