line output convertor where to install?

[colind]

2010 laramie 3500 with the alpine system. Looking to install my sub and amp and looking at an audio control lci2 line output convertor. Heard you can install directly onto the wiring from the factory amp to the sub. Is this correct will I get all frequency?? Any help would be appreciated also is there a different line output convertor that would work better or easier??

 

[baum]

if your just doing a sub and you have a factory sub yes use its signal.