Aftermarket sub with stock headunit?

[sjfarney]

Im trying to hook up a sub to my stock HU but when i pulled the head unit out there is no RCA plugs. What exactly do i need to accomplish this task. Thanks

 

[irocdupi]

Its something called a Hi Low convertor. Pain in the ass to hook up but I got my sub going off the stock head unit and plays nice. the bass sounds awesome with pink floyd

 

[lounge lizard]

or an equalizer

I have one in my truck that I run off the rear speakers and then to my amp to my subs