This 3 channel 15 LED spectrum analyzer is the perfect addition to any audio amp project. It produces fantastic displays on three LED bars that can be individually adjusted for any particular frequency range. The circuit will take line level output from most any audio source, and operates on 12V DC. This means that it can even be run in a car.
Notes:1. The circuit expects line level inputs. If you connect it to speaker level, you will have to readjust the circuit every time you change the volume.
2. After the circuit is connected, apply power and signal. Now adjust the pots until the corresponding group of LEDs reacts.