Hi, I'm looking for a little bit of guidance here. I'm trying to build a circuit that will take audio input from an electet microphone and light up LEDs to a bass beat. The thing is though, I dont just want them to light up, I want them to fade in and out, glowing brightly when its loud, not at all when there is no noise, and glowing at an appropriate level everywhere in between. So I need to know what will be required to get this working. My idea right now is to use a comparator fed into a transistor to light the leds. I'll send a sawtooth or flat line into one input, and the audio signal into the other, varying the duty cycle, thus shining the led dimly or brightly. With all of the right preparations (amplifier, low pass filter, etc), will this work? What else will I need to do? Also, I really have no idea about how to build an automatic level control, which I figure will be a necessity if I don't want to be constantly fiddling with a control knob. Can anyone point me in the right direction for that as well?