Triads over dominant chords

[Robert]

Hope this is useful.

 

[sunvalleylaw]

Hey Robert, thanks! That is a fun idea. Is it the fact that it is a dominant chord that makes the triad from a whole step down work? Something about the minor seventh of the root that that creates crossover? Using A7 = A - C# - E - G, (or A9, A11, A13 as you say) it somehow creates crossover with G= G, B and D? Weird how that works for the ear. Something about adding that G note helps us access the reset of the G triad? Cool. Will have to experiment. I need to get a looper again, and use also my Digitech Trio and mess with it.

 

[Robert]

Yes, the dominant chord has a b7 instead of major 7. You can't use this approach for a major 7 chord, because of that.

Another way to look at it is that if you add the A and G major triads together, you "almost" get the Mixolydian mode. Only note missing is the 6th.

A major triad - 1 3 5
G major triad - b7 2 4 (or b7 9 11)

You can also use the G major triad over an A minor chord. The A minor chord has the notes from G major in the scale/mode for A Aeolian or A Dorian!