small sub

Yes, but it will be QUITE ineffectual. FAR too little power to do any kind of good. By the time you figure the losses from the LARGE inductors you have to add for low-pass functions, you are looking at a fairly heroic waste of time. As a suggestion, look into an amplified tube, like a Bazooka or Rockford Fosgate. Still small, and amplified. Some of the smaller ones can even be powered from a 12v acccessory power outlet or cigarette lighter. ....15It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."