Capacitor Value in Bass amplifier to speaker circuit
In your diagram, the speaker is shown as a simple resistive load which is far from reality. In fact, the speaker is a reactive component (see Thiele-Small equivalent circuit). This implies that the whole output circuit has a (hopefully) well designed resonant characteristics, which in turn depend on the capacitance.
I'd recommend choosing the capacitance as closely as possible. I believe that 2200uF should be well within the actual manufacturing tolerances (which are usually high for electrolytic caps).

The voltage rating should be not lower than 80V of course, but it also should not be much higher as well (like 250V or higher for example), but I don't think you could fit a high voltage cap in there anyway.