I have a subwoofer that I believe has a built in amp. (Altec Lansing ACS54) This subwoofer plugs into my computer with the standard green line out jack. If I wanted to use an external amp, could I use the "all-in-one" subwoofer as an amp still by pluggin it into the c/sub port? Or would I be better off splitting the green line out cable into the amp and subwoofer, and then just not pluggin any speakers into the subwoofer? Any feedback is much appreciated (including telling me if this entire idea is even worth it ) Thanks!