Can someone please explain the theory/use of the zone sliders in parametric curve and how the 3 sliders relate to the 4 controls. I see that the grid divides the tones into 4 areas which can be controlled by the 4 tone sliders, but how does one set the 3 zone sliders to correspond. What would be a good starting point?
They control the crossover points between the 4 tone sliders. I don't know of a really good way to explain it but if you play around with them it should become more clear.