Does anyonw know of a schematic out there that will make a LED flash to the beat of the music? I'm building a sound system in my car and I want to make led's flash to the bass beat from the subwoofers.
You would be well advised to add a low pass filter and a voltage divider on the input of the transistor. Otherwise the signal strength may cause the LED to remain on. A low pass filter will only allow the low end bass sounds through, but in doing so, you may need to amplify the stage somewhat.