YourITronics

Here is a new version of the classic color organ, where different color lights are triggered by different frequencies of sound, resulting in a display that flashes along to music. In this case the newer type high intensity LEDs (3000 – 5000mcd) were used along with a very simple discrete transistor drive circuit. The design goals included small size and excellent portability, as well as long battery life.

LED Color Organ: [Link]