I have an OLD speaker i found (JL audio) 10". It has no writing on it. I hooked it up to a CD player i have with some speaker wire and held it over a bucket, it sounds pretty good, maybe a little dull but that could easily be the bucket. My question is... How do i know if it is a subwoofer, or just a speaker? or is there even a difference. I offered it to a friend to use as a sub in her truck (she has an amp of her own) will this work, or should i just scrap it?
take a couple of pictures and we might be able to spot a thing or two that will help answer your question.
looks like a medium throw subwoofer, probably 10mm xmax ballpark i'm just total guessing.
if you have a multi-meter and can check the resistance that might give a clue as to the status of the voice coil. otherwise, i don't see any reason not to fire it up. most car subs were designed to work in smallish enclosures and sealed is much more forgiving than ported, so...
maybe a 1.0-2.0 cubic foot sealed enclosure and see how it goes? probably a 100-200 watt amp would be safe and fine. i don't know...something like that probably isn't too far off the mark.