WOW, some people dont know alot at all. Now I see why people dont bother coming into these forums.
Based on your amps, you should have atleast 4ga wire front to rear and 4ga ground to solid clean body. 8ga to each amp shorter the better. Run RCAs on other side. Bigger amps like 2 1000ds or bigger you should upgrade to 0ga wire.
It has nothing to do with ANY of the stuff they are claiming.
Try swapping the speaker wires. take the wires from the one sub and put it to that one acting up and hook up the other. If it travels to the other sub now, your down to the amp. So the to make sure it is play with the adjustments, see if it goes away. If still there swap the rcas. And if it dont work for the hell of it swap the power wires. If it goes away swap back one wire at a time and when you find it replace that. If after all that your still getting that noise the amp is your problem which is what I would be thinking anyways.