Lower Voltage LED organ
The "5th" opamp is a virtual ground so that you other amps have a DC offset. This is done because you're using a single supply (just 'positive' volts). No matter what input voltage you pick, this circuit will take half and use it as the negative rail for the op-amps. 

In that sense, this circuit is robust enough to handle the voltage change well. However, the LED's in series will probably need to have their current limiting resistors changed so that they get enough juice from your lower supply. I think that's all you'd really need to change. This circuit just lights up according to the frequency of the input right? I'm just looking at this at a glance.