This is what I got in an e-mail from a Musicology professor. Hadn't seen any one mention it in here before.
Quote:
The piece in “Soul Controller” is the slow movement of Bach’s Brandenberg Concerto No. 1; the RZA took the very opening phrase, with a prominent oboe solo, and looped it, then overdubbed two versions of it onto each other, and also added a flute solo that imitates the melody line. Of course, that all is combined with Sam Cooke’s “A Change is Gonna Come”...