NB: This is all in Tenor Sax key (Bb), not Concert
I've been mulling over the following excerpt of a Chris Potter solo on the tune "Just One Of Those Things," I find it probably the most harmonically and melodically puzzling part of the solo. I'm trying to figure out if there might be some underlying logic for the particular section of this solo (1:56 - 2:04 in the attached video) bracketed in red here:
(The reason for the note about the "G Tonal center moved up" is because it is hard not to notice the similarity to the G-7 arpeggios preceding it; it's pretty fascinating how well-balanced of a phrase it is)
The Question: He seems to be emphasizing the B naturals, then targeting A natural twice, using fairly complicated ways to get to the A. I'm hearing this as a strange way to "target" the key of Bb, notably because he starts with a G-7 arppegio (i.e., the relative minor), hits Bb's flat 9 (i.e., B), and then uses great embellishment to get to A twice (the leading tone) - the second time he targets A it seems to come from an F7 sound; and easily the most striking sonority in this excerpt (possibly in the entire solo) is the way he kind of drop-kicks in with the D# minor pentatonic (i.e., Eb minor pentatonic, the iv chord of Bb) which leads into the F7-ish sound where the F#-7b5 is. Obviously he then resolves the F minor sound to the C major sound (i.e., iv -> I), which seems to give more credibility to the F7-ish sound (i.e., F7 which turns into F-7). This would mean that we are getting a kind of Bb-ish sound, to F minor to C major. Does this sound legitimate, or am I reading too far into this? Does anyone hear something different going on? This has been bothering me for a few days, so any input or corrections would be fantastic.