2010 denali xl sub hum

[Dub2001]

Asking for a friend. Just installed an aftermarket sub and amp in a 2010 denali xl using the factory head unit. Its the nav system with no anc. Sub is ran off a line level converter tapped into the factory sub output in the center console. Everything works great until the driver door closes then the sub hums. Starts quiet and builds to a loud hum. Stops as soon as the driver door is opened. No other doors affect it. Customer doesnt want to change the factory head unit. Im stumped. Anyone ever deal with this?

Click to read more...