yes, the SSF is on, but same problem still exists

 

did the hook the line out adaptor or hi inputs to the factory sub, if so that could be part of the reason your only getting real low bass threw the subs. i had the same problem in my gs until i wired to the full range speakers in the doors

 

Can you post a picture of your amp with the settings? Also, did you turn down the bass eq on the factory headunit? I've had that problem before in my gx. I didn't turn the bass all the way down and when the bottom drops, i'll hear the lil 6.5 sub in the back just rattling, poor lil guy.