So I have had two pontiac torrents a 2006 I had a aftermarket stereo, 4 chan, and mono. Now I have a 2007 torrent stock radio, fosgate high low converter, all new fosgate amp and fosgate speakers. Both my cars had a loud hum I cant get rid of. My amp ground is .3 ohm when I check it my high low converter was below one ohm and my radio is grounded well. I've tried running 2 new rca wires above the carpet away from anything else in the system. I'm not getting any difference in noise. Is there any other grounds that could effect this. Is my radio itself making this annoying noise. Reminder I've had aftermarket radio in last torrent. No other car I've owned has had this problem. Help please trying to avoid ground loop isolator seems like a bandaid