This is more an exercise in me trying to understand things than anything else; bear with me please. Suppose we had two tone circuits set up in parallel (see the attached diagram - hopefully I did that right). Now suppose that the two caps have the same value. If I set the pot on cap 1 at about the middle, it bleeds of a certain amount of "sound" at and above a given frequency (and correct me here and anywhere else if I'm wrong). Now as I turn the pot on cap 2 up, it starts to bleed even more of that given frequence off, right? So I could get the same effect just by turning pot 1 a little more, at least to a point. But if I have both pots turned to zero resistance, then I've just got two caps in parallel. These add, so now I'm bleeding off a different set of frequencies than before, right? So first question, at what point does that happen? If I've got pot 1 set to zero, is it a really abrupt transition that won't take effect until pot 2 is really close to zero too? Or is it more gradual? Or is there a way to make it gradual? Second question is what if the two caps have different values? My weak understanding is one would bleed off higher frequencies, and the other bleed of lower frequencies (plus even more of the higher frequencies being bled off by the first cap). Is this correct? And then as both pots reach zero, would it bleed off even lower frequencies?