I had to take out my subs to pick up a new bumper and some other stuff, got back around to putting them back in today and I noticed once I wired them all back up they started making a heartbeat sound.
Usually this would be a bad ground, so first I sanded the ground point down even more so, this didnt work. Then i tried changing to another ground point and sanding this down like crazy, didnt work. So i tried a 3rd ground point under the seats, that was abit better.. However when i turn my key there is a sort of popping sound and then they seem to be picking up interference from the engine now.
This problem never happened before when i had them wired up and i never heard it in my old car.... Its just abit of a pain the rear end. Before only one sub was working though, now the pair are working?
Could this be a problem with the 'Main ground' to the battery or something like that? if there is such a thing? as before now ive had problems when braking at high speeds it cuts out my stereo and lights for a second? If so where would i find this connection?
I have : 2x JBL GTO1202D 1200w and a Juice JA690 Amp.
The reason im so confused is because less then a week ago it was all working fine and all i did was take out the wires and the subs then put them back in? Ive been through ever connection that ive made to the kill switch and the RCA cables and i redid these to make sure they were fine, but i still have this sound!!

Thanks for any responses, would really help me out!