How to test subwoofers?

[audaciousgoat]

I got an old Sony STR K840P 5.1 600w amp that came with all the original speakers, and I'm looking at upgrading the weak 100w subwoofer. I figured, instead of spending +$100 on a sub on amazon, I would check out all the subs they have at goodwill all the time. Is there a way to test them without my amp? I've heard that you can plug a battery up to it or something but I'm not sure how to do that either. The only port my amp has for a sub is "subwoofer wire", no speaker wire to the sub.

 

[Rogue Leader]

You can't hook a battery up to a powered subwoofer, you need some sort of audio source. If its unpowered you could hook a battery to its positive and negative and tell if its totally blown, that said you still wouldn't know for sure without listening to it if its on the way out.