The alterated scale is usually played over dominant 7th chords. It doesn’t have a clean 5th, though, but the notes of the scale fit perfectly as “higher chord options”. That means, the b2 can be interpreted as a b9, the –3 can be interpreted as a #9, the +4 as a #11 and the +5 as a b13. These are the chord options that work for chords that are really used as dominant 7th chords (not necassarily all chords of a blues, since those are blues chaords and don’t have the function of dominant 7th chords

Last modified on Monday, 25. September 2017