I installed an amp and aftermarket speakers into my mustang but am getting an annoying humming threw all 4 speakers but only when the car is running is there anything I can do to eliminate this or should I just buy a filter??

 

YOu more then likely ran your low voltage rca's next to your high current power wire. Its called interference.

 

nope they are on opposite sides of the car

 

anyone else?? ADVICE!?!?!

 

I`m no expert, but when my install made noises, I had to put in a in line filter to kill the noise from the alternator

 

A filter is a band aid, it covers up the problem but doesn't fix it.

you left the factory radio in and yer using an loc?

 

all after market jvc head unitmb quartzcomponent speakers all round running off a older 4 channel kenwood amp till I got the spare 600$ to spring for a nicer amp

 

Might be because the gain is too high?

 

ill check it in the morning

 

where is it grounded? try a different source(mp3 player with a headphone to RCA cable) and see if it goes away. You can also try running a 2nd set of rca's just temporarily above the carpet to see if it helps. you could have a bad rca.