I rarely ever listen to any Steve Winwood on purpose, but when he comes on the radio I'm never disappointed. This song was playing at the store while I shopped today, and when the sax solo started (at 2:11) my first thought was "is this a direct ripoff of the sax solo on Aretha Franklin's Respect?" No, it is not, though similar in length and style. Perhaps it is an homage, or throwback.
My second thought was "what are these chord changes?" The song is in G, but here are the solo changes:
In order:
Em (VI) - relative minor, completely expected
Bb (bIII) - borrowed chord, tritone away, unexpected. Lasts long enough to feel like a new key.
Dm (v) - this would be the iii chord in Bb, so it's not as dramatic. Just reenforces the new tonal center.
Ab (bII) - ah, another borrowed chord a tritone away. This is a pattern, but it now sounds like the bVII in Bb. There's a kind of Lay Lady Lay thing going on.
F (bVII) - this is the actual bVII in G, but it looks more like a V chord in Bb, a turnaround like the end of the bridge on Dock of the Bay. Instead he just jumps back into the chorus in G. If the vocals weren't already so crazy high, I would have thought this a good opportunity to modulate up into Bb completely. It definitely takes a little journey, at least. The solo is short enough, though, that you have the original key in the back of your head the whole time.
I would bet that this is the only popular song that has used that chord progression, maybe ever. I've certainly never heard it anywhere, so I have to give major props for originality.
