Gamesetwatch has a nice interview with both the Sound director and composer of the mega hit that is Street Fighter IV.
From the interview: " GSW: What sorts of objectives were driving your work on the Street Fighter IV soundtrack?
Endou: For both the music tracks and sound effects, we thought a lot about what would have an emotional impact. Choreography was very important. While we could rest assured that Fukasawa-san's songs sounded great, we knew the effect would be compromised if the timing were off."
I must say they both did a terrific job, and the remixes of the old sf2 themes are awesome and so is the characters themes, not to mention the excellent Japanese voice work.
Check out the full interview here