Watch the Club 54: 7 online guitar lesson by Chris Buono from Guitar Cubed
There have been a couple mainstays throughout Guitar Cubed such as double stop bends, motivic development and what is happening here between Guitars 1 & 2. Call and response is the name of the game here in the foundational parts of Club 54 with Guitar 1 throwing down those delicious m7add4 type chords on the downbeats of each bar for the call. In the first three bars Guitar 2 answers back with 5ths built from chord tones within the chord they’re played over. In fact, they’re the same 5ths that are played at the top of the Guitar 1 re-voiced m7 chords; just an octave lower.
When it comes to the Gb13 in bars 4 and 8 (remember Club 54 is an eight bar jam) the response is another thing entirely in you get two different versions of it. In bar 4 you have another substitution working to bring out some outside harmonies with a G#+ triad coming in at beat 2. Though, it's important to note augmented triads are symmetrical meaning all the chord tones are roots and one of the notes in this chord is in fact C so this could just as well be looked at as a C+/G#. The final harmonic instance in bar 4 and the downbeat of beat 4 is a crucial one as it’s an alternative voicing for the venerable 7#9, aka the Jimi Hendrix chord. Look familiar? It should because you played it in bar 12 in Down and Dirty at bar 12. The second time around in bar 8 you have the 7#9 voicing we know all too well and for good reason--it never, ever sounds bad. Feel free to play it 'til you drop.