well i was thinking ... can i buy a sub encloser that fits 2 subs but use one? and have the other wires to be put later in, for the other sub? and another question is that can i use 2 different subs?
im confused why u would ever want to do that, but you could if u wanted to. make sure there are two separate chambers for the subs in the box. just dont hook the wires up for the other sub. you could use different subs too if u really wanted too. wouldnt recommend it since different subs sound differently and have different responses.
a: if the box is divided then yes you can run one sub. If the subs share airspace then no. I'd not suggest using two different subs. They won't work as well together and you'll get a worse end result.