I guess I need to clarify alittle more. I'm using the 4017 as a frequency divider, the clock of the 4017 is connected to the output of my LM3915. Then I use a single output of the 4017 and connect that to all of the clocks of my shift registers.
My thinking behind the DC rectification was that for the long bass notes, the DC voltage would remain somewhat constant, then whenever this note changes amplitude, the DC voltage would also change. I'd then have a differentiator op amp detect this change, which would then control my circuit. I'm not quite sure how I'd go from the differentior to my circuit just yet, but I wanted to see what you guys thought about my plan thus far.