Capacitor rules : Is this correct?

[Le québécois]

Hi capacitor value (µf range)  = all audio frequencies can pass (20 to 20000 hz)
Low capacitor value (pf to nf range) = restrict Bass frequencies

I'm aware of the RC equation : 1 / (6.28 * R * C) so I guess my question is more related to what happen when I put a capacitor in serie (passive) with my guitar signal and were the resistance is 0 (at least it look like it).

Also, If my interpretation is correct Higher input and output capacitor values would be required for converting en FX from guitar to bass. Right?

thx

[R.G.]

No. You're close, but not quite there.

The problem is that a capacitor can pass all frequencies or almost none depending on what else is involved. What you're missing is that there is *always* something else involved. The case you mention where a capacitor is in series with a guitar signal, presumably in the cord, has a resistor before it and after it. Whatever is driving the cable has some internal resistance, and the device taking in the signal has an input resistance. These have to be considered in the RC equation, which still applies. This means that it is impossible to say that uF caps pass full audio and nF restrict bass. It all depends on the source resistance and load resistance, which may or may not be actual resistors you can touch and feel. They may be hidden inside active devices, but they're still there.

Yes, higher value caps are required for bass if everything else is the same.

[CynicalMan]

The reactance (AC resistance) of a capacitor is equal to 1/(2*pi*f*c). So the reactance of a 10u capacitor at 1kHz is only 16 ohms, but the reactance of a 10nF capacitor at 1kHz is 16k. As with resistors, the current that passes through a capacitor depends on the rest of the circuit, but you can treat the reactance as resistance in AC analysis. How you adapt an effect for bass depends on how much low pass filtering there is, but if it does affect bass frequencies, you can increase the capacitors' values.

[Le québécois]

This was a Pandora box question. Obviously! But thank your explanation remain very clear and definitely help my understand a bit more.