Space plays and stops
- Notes and intervals
- BbM3Dm3Fm3Ab4C#
- Extends
- Bb Dominant 7
Bb Dominant #9, written Bb7#9, is built from Bb, D, F, Ab and C#: the root, major 3rd, 5th, minor 7th and sharp 9th.
Its 3rd and 7th, D and Ab, are its guide tones: they say what kind of chord it is, so voicings are built around them and the root is often left to the bass. E7, a tritone away, has the same two notes the other way up, so it can stand in for Bb7#9 as its tritone substitute.