Space plays and stops
- Notes and intervals
- GbM3BbM3D2Fbm3G2A
- Extends
- Gb Dominant 7
Gb Altered, written Gb7alt, is built from Gb, Bb, D, Fb, G and A: the root, major 3rd, sharp 5th, minor 7th, flat 9th and sharp 9th.
Its 3rd and 7th, Bb and Fb, 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. C7, a tritone away, has the same two notes the other way up, so it can stand in for Gb7alt as its tritone substitute.