simple sound to light circuit designed as an add on for a dalek voice mod i built a while back....you can add a preamp before the line amp if you wish to amplify any audio signal from a microphone(electret etc)
circuit shows 3 leds but u can add more if you wish(within reason...) i used 4 hi brightness blue leds
that is exactly right they were reversed ive uploaded a replacement pdf file with the error corrected....gremlins must have swapped things round when i did that schematic...........