Audio input/output capacitors?

I've recently been fooling with some discreet audio amp designs. In looking at various examples on the web, I notice a wide range of coupling capacitor values in the schematics. Seems to vary from hundreths of a uF to several hundred uF.

Is there a guideline or rule of thumb based on parameters of the circuit to help choose a proper capacitor? I would guess frequency of the intended signal would be the main determining factor, but so far any rules have eluded my brain..

Any recomendations for helping me clear this up in my head will be appreciated.

Thanks Aaron

Coupling capacitor form high pass filter with impedance (resistance) seen by the capacitor. So we use this equation

[LATEX]F_c = \frac{1}{ 2 * \Pi * R * C}[/LATEX]

So

[LATEX]C = \frac{1}{ 2 * \Pi * F_c * C} = \frac{0.16}{F_c * C}[/LATEX]

And cutoff frequency sets the the low (bass) frequancy.

**broken link removed**

Thanks Jony130. That's exactly what I was looking for. Aaron