Watch the 1 5 1 9 Structures online guitar lesson by Brad Carlton from Guitar Lab: Open String Universe

This lesson uses a root fifth root ninth structure on the 6th through 3rd strings combined with the 2nd and 1st strings open.

Voicing 1 is an F#9sus4 voiced 1 5 1 9 4 b7. Mixolydian, dorian and aeolian apply. Voicing 2 is a G6/9 voiced 1 5 1 9 3 6. Ionian, lydian, mixolydian and overtone apply. Voicing 3 is an Ab m addb6 voiced 1 5 1 9 b3 b6. This chord is a subset of the aeolian mode.