Hello, I suppose… Magician posted it here http://forum.arduino.cc/index.php?PHPSESSID=h35fsns7ltuls6qpoe2pki8bs4&/topic,164915
IMHO, there is nothing better than FFT for band pass filtering, explained here:
http://coolarduino.wordpress.com/2012/06/28/stereo-audio-vu-meter-on-arduino/
When I have more time I will read the article.
Thankz for your post!! 