There are three flavors of noise on top, and the middle one is normalled to both bandpass filters.The next part is two identical Swiss Army knives. You can do straight sample & hold of an external voltage, mix it with the classic smooth fluctuating Buchla random voltage, pulse it, control the rate of fluctuation, whatever you want.The bottom part is basically two separate sections of a 291e filter. Very powerful.I've owned this for at least a year, and it has received minimal use.