Behind the Scenes
The lights are syncronized to music using a micro-processor based computer controller which uses digital signals from the computer and translates them into a musical light show. The product I use allows me to have complete control over all of my Christmas lights.
The music you hear is from the same computer, and is sent to my amplifier and then to the many outdoor speakers that are placed throughout the display. The music is also sent out to a FM transmitter and broadcasted on 97.5 FM which is how you can hear it in your car.