The original version of this project used a standard electret microphone to pick up the audio and the FFT Arduino library to analyze the signal. I was not happy with the response; it was not clear and despite all of my attempts to tune it I could only pick up 3 or 4 channels at most. In a previous project I used an MSGEQ7 spectrum analyzer and it worked fantastically. I also added an external gain knob to adjust the response on the fly.