Here's why: I had bought 2 Altec Lansing 12" 50 watt subs a coupla years ago, one of which died. Since then they have gotten out of the HT/Audio biz and now only manufacture for PC's. The Pro Line, although using the AL name, is actually made by someone else. So..the long and short is although under warranty...no one can fix this, so they gave me 99% of my money back from the purchase. The power went belly up in this, speaaker is fine and I do have a need in The Lobby/Green Room for a passive sub..so... What do I need? Where do I crossover? How do I wire and figure out ohms and all? Stuff like that. Thanks in advance.