Space plays and stops
- Notes and intervals
- A#m3C#m3Em3G
A# Diminished 7, written A#dim7, is built from A#, C#, E and G: the root, minor 3rd, flat 5th and diminished 7th.
Its 3rd and 7th, C# and G, 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.
In the progressions here, A#dim7 is the ♯i°7 of the Diminished Passing Turnaround in A and the ♯iv°7 of the Jazz Blues in E.