Watch the Missing Thirds online guitar lesson by Brad Carlton from Chord Studies: Evolving Blues Vol. 2
This is a shuffle feel with A as our tonal home base. We start with a nice modern voicing of the A7add4, which creates a nice tension between the three and the four. Then we move to a D13 with no third, which utilizes the same half step interval as our first chord. The same voicing is used for the C13, we just move it down one whole step.