Interesting interview from Downbeat Magazine’s May ’78 edition, where Zappa talks (among other things) about foreground vs background in music and how he approaches the issue:
The chord is like the establishing shot in a movie–where you see the exterior of the building, or the alley with the garbage cans. It tells you where it’s happening. Then the action takes place. So you have a chord, and you have three notes that provide certain types of emotional activity versus the chord. And that emotional activity is redefined every time you change the order of the notes and the space in between the notes. (…) But what’s really happening in the solo is this: for each harmonic climate that’s presented, there are experiments being conducted, in real time, with different notes and weights and measures of those different notes, versus the climate. And every time you change the position of the note, it has a different impact.