single sub connection

[Raven766]

i have a sony ipod docking stereo there is only left and right speaker direct wire cnnections how do I wire a single sub to this type of steeo

 

[ssddx]

http/news.cnet.com/8301-13645_3-57579269-47/how-to-hook-up-a-subwoofer-to-a-stereo-system/