Space plays and stops
- Notes and intervals
- CbM3Ebm3Gbm3Bbb
Cb Dominant 7, written Cb7, is built from Cb, Eb, Gb and Bbb: the root, major 3rd, 5th and minor 7th.
Its 3rd and 7th, Eb and Bbb, 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. F7, a tritone away, has the same two notes the other way up, so it can stand in for Cb7 as its tritone substitute.
In the progressions here, Cb7 is the IV7 of the Basic Blues in Gb.