im very new to car audio. my problem lies with when my volume of the HU is all the way to zero and i go to my subs there is a faint noise its hard to explain well it's kinda like a hum or a buzz but very quite i tried the ground loop fix by grounding my rca's to the HU and that helped a bit since the noise was louder before and that got rid of it then i found a better bolt for my amp ground so it was more secure and that did not help. so idk what could be the problem. my setup with the problem HU: pioner DEH x3500ui subwoofer: one kenwood kfc w3013ps other sub is unknown i was told from the seller it was an older kenwood but im thinking it is a home thearter subwoofer. AMP: Kenwood x1200m refurb from ebay. the power and ground wires for the amp is 8 awg. Vehicle: 2000 toyota camry le anything else you need to know let me know