Fig. 1 · Bb to Db

interval

B♭ minor third

B♭lowerD♭upperm33 half steps

Three half steps. The interval that makes a triad minor.

On the keyboard

BbDb
Fig. 2

What is true of it

B♭ up a minor third is D♭: 3 half steps, and 3 letters counting both ends.

Turn it upside down — put the B♭ on top — and it becomes a major sixth. The two numbers always add to nine, and the two sizes to twelve.

It is a imperfect consonance.

Every interval on B♭

B♭ → C♭minor second · dissonanceB♭ → Cmajor second · dissonanceB♭ → Dmajor third · imperfect consonanceB♭ → E♭perfect fourth · perfect consonanceB♭ → Eaugmented fourth · dissonanceB♭ → F♭diminished fifth · dissonanceB♭ → Fperfect fifth · perfect consonanceB♭ → G♭minor sixth · imperfect consonanceB♭ → Gmajor sixth · imperfect consonanceB♭ → A♭minor seventh · dissonanceB♭ → Amajor seventh · dissonance

C m3C♯ m3D♭ m3D m3D♯ m3E♭ m3E m3F m3all 204