I have an old aftermarket deck and speakers in my car and i just installed a bass controller and sub with custom box. I believe the bass controller is a potentiometer but i could be wrong. My speakers cant handle much volume without distorting so i bought the controller hoping i could raise the volume to the sub to the max but it doesnt work as i planned. For example volume twenty with gain on amp and controller to the maximum is not making the sub as loud as it is on volume 50 but then my speakers are sounding horrible. is there a way to push the large portion of the power to the sub and not the speakers?