I already implemented a color organ with 4 leds. You plug a music input and it turns on the leds as the music goes (one led for bass, other for mid-low, other mid-high and other for highs) and it works fine. It uses Fourier Transform to get the spectrum of the sound.
What I really want to do is use four 10watts RGB led lights instead of 4 simple leds so I can light up a room. I know this RGB leds have 3 pins (one for each color) and can be driven by PWM, if the input of the 3 pins is zero, then the light is off.
And I also know I need a driver to turn a one color led on, like this one: http://www.tbideas.com/blog/build-an-arduino-shield-to-drive-high-power-rgb-led/
I think I need three drivers per led as these are RGB, and also as there are only 6 PWM outputs on Arduino, I need a shift register, like this one: http://www.elcojacobs.com/wp-content/uploads/2012/08/shiftpwm_74hc595_RGB.png
1- Are the general connections of the schematic ok?
2- If the led is RGB I need three drivers per led, right?
3- Will the shift register work ok?
4- Do you think that PWM shift register will slow down considerably the speed of Arduino? Because Fourier Transform is sensible to the speed.
Thanks a lot for your time!