I like the red noise as a modulator, it is the most like a burbling random lfo. The other ones' high frequencies come through and sound like noise, albeit different noise from just mixing in the audio with the noise volume.
One thing I would like to figure out on the matrixbrute is how to do impulse/comparator noise- its like a square wave, either off or on, but at random times. It ends up sounding like crackle.