Shunted half baxandall - an idea

[phasetrans]

All,

I whipped this up in LTspice, but it's sat for months waiting for a board spin. I don't see getting to it before Halloween, so maybe someone can breadboard the main idea around U4 and see if it is usable?

D5 and R16 can probably be any variable or thresholded impedance element. I picked the values by looking at current in D5, and then replacing D5 and R16 with an equivalent shunt Z, and then made Bode plots based on that shunt value.



It is audible and stable inside LTspice WAV simulation, but that doesn't mean the real world is kosher.