Can someone explain this tone circuit?

[Unknown_User]

On 13/10/2018 at 18:35, tauzero said:

Capacitors of whatever value present a higher impedance to lower frequencies than higher frequencies - the impedance doubles when the frequency halves. To give you some idea of values, at 100Hz (somewhere round E, 2nd fret of D string, with apologies for any inaccuracy) 10nF would be an impedance of 160k, and 100nF would be a tenth of that. So imagine a resistor of 320k replacing the 10nF capacitor when you're playing bottom E, 160k when you're playing an octave up, and 80k another octave up, and you'll see how the circuit behaves.

Thanks very much for explaining that.  I think I've managed to get my head around it!