Kenwood 500W Class D Mono Amplifier with Crossover "sub car humming" Questions

...car and when i do that some times when i shut the door it makes my subs make a loud humming sound. it started to do this when i turned my amp power up over half way. i am running a 4gauge power and ...

sub and surround speakers (radiation via leads possibly?). The problem disappears if the TV is off. It is reduced by running a direct earth to the shield of ANY input sockets (any, RG, 232, HDMI, RCA)