ok, i have a fi q 18 and when I have the volume down at about 15 (out of 40), it's fine. but when i turn the volume up to about 20-25, the bass still hits, but it seems as though the sub is pulsing at the same time. I have not checked the connection on the acutal sub as I am at work right now and can unscrew it. I checked the connection from the amp to the back of the box and it's fine. Like i said, the bass hits, but it's noticeably lower since it seems like two signals are going to the sub or something. I have a Hifonics 1606D. I am using the rear outputs of my radio and I don't know if that's the problem because in the manual it says that I should use the mono output, but I just haven't got around to doing so. any help would be greatly appreciated.
