audio input to pwm

Hello peeps! been a while since i posted on here!

anyway, i'm about to start work on a project based on the tutorial about led colour mixing with 3 potentiometers )this one http://www.arduino.cc/en/Tutorial/LEDColorMixerWith3Potentiometers ).

basically i intend on taking an audio signal and split it into bass, middle and high frequencies using some simple filter circuits. with these three frequencies connected to the analogue inputs instead of the potentiometers, i hope to drive the rgb led in time with the music, like an old colour organ.

has anyone tried this sort of thing before? i havent got the parts yet, but i'm not sure if i'll need to amplify the audio signal with an LM386 ic.

cheers,

bod.

thanks for the tips on the passive RC filters daniel! its appreciated.
the intention of the project is not to make a colour organ but its the effect that i'm hoping to produce, as i'm using the led to indicate that the code and frequency imputs work, before implementing the idea into yet another project, that requires sound to drive motors and relays.

i was playing arround with filter circuits this morning, but really could do with an osciliscope to make sure its right.

cheers,

bod. :smiley: