Can I use a passive sub in a home theater?

Question

Can I use a passive sub in a home theater?

Answer 1

Of course, you just need an amp to power it.  

You will run the sub/LFE output from your receiver to the amp via RCA cable and then speaker cable from the amp to the sub.  

It's what I have in my my home theater and it works perfectly fine!

Answer 2

Some passive old subs have a center tap in their coil, such that you connect each side (L & R) of a stereo signal, the sub will then add both signals. Sometimes they include a cross-over for the other speakers.

If that is the type of sub you have then it may not be good for a 5.1 setup. You could probably tell by the terminals it has.