interval
B♭ minor sixth
B♭lowerG♭upperm68 half steps
Eight half steps. The major third turned upside down.
On the keyboard
What is true of it
B♭ up a minor sixth is G♭: 8 half steps, and 6 letters counting both ends.
Turn it upside down — put the B♭ on top — and it becomes a major third. 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♭ → D♭minor third · imperfect consonanceB♭ → Dmajor third · imperfect consonanceB♭ → E♭perfect fourth · perfect consonanceB♭ → Eaugmented fourth · dissonanceB♭ → F♭diminished fifth · dissonanceB♭ → Fperfect fifth · perfect consonanceB♭ → Gmajor sixth · imperfect consonanceB♭ → A♭minor seventh · dissonanceB♭ → Amajor seventh · dissonance