bigger or smaller than what? what size subs are we talking about? what's your goal? SPL? SQ? how much power are you applying to the subs?
Generally, for a 12" sub for example, you can go between 2-2.5cu ft per sub, and tune the ports accordingly. For SQ, aim for 28Hz. larger for SPL, smaller for tighter detail and punchier response for SQ. Larger will also help a little with mechanical power handling capacity