Big Muff Pi Clipping Stage

[Khas Evets]

I've been toying with the BMP clipping stages in my spice simulator. The cap before the diodes seems to both block DC and function as a high pass filter. If I'm correct, that means the upper frequencies are passed through the diodes creating frequency dependant clipping. I'm also guessing that he coupling caps between stages of the same value are limiting the bass, so it doesn't get too muddy. A few questions:

1.  How would I calculate the cutoff frequency of the coupling caps?
2.  If I change the caps, is it a good idea to change all caps to the same value (interstage caps and diode caps)?


http://www.generalguitargadgets.com/diagrams/bmpsc.gif