Engine noise thru speakers

im running a 12" sub, 5.25" component set off a 4 channel amp. it all runs fine when the key is on ACC, but as soon as i start the engine I get engine noise which rises and falls with the revs. Ive tried moving the earth, moving the power lead away fom the other wires (not a huge distance away tho) and checking nothing is shorting out, seems strange that it would only do it with the engine going but is fine in ACC, any suggestions please! :)

Do you have the paint scrapped off where you have the amp grounded at? Is the ground the same size as the power wire? Check for breaks in the rca's or even having lower quality rca's can have that effect. Let us know.Sound Pressure

You know you have the right amount of pressure when your eyes start to water! Now you've got Juice!

Ive scraped off all the paint, the cables are the same gauge, and the RCA`s are new performance series ones, my mate said something about a little box (thats all, didnt know what it was :) ) that you need for some head units cos hes got one for his, I`ve never heard of it before, perhaps someone nkows what it is, and will it help? im pretty sure its not the wiring, as I`ve tried disconnecting the left channel, right channel, and sub seperately but still get the same thing, so maybe this little box thing (whatever the hell it is!) is the answer?

Your answer would be a ground loop isolator.Sound Pressure

You know you have the right amount of pressure when your eyes start to water! Now you've got Juice!

Brilliant, I`ll give it a shot, cheers :)

Good Luck!! Let us know how it goes.Sound Pressure

You know you have the right amount of pressure when your eyes start to water! Now you've got Juice!

Another thing that you should consider is a low battery and a weak alternator. This is always overlooked when it comes down to ground loops as it's not a visible problem to most people. Get the charging system looked at or do it yourself, but make sure that your electrical system is getting atleast 14.4 volts while the system is running and 12.5 volts when the car is off. Jeff

Velocity Custom Home Theater

Mobile Audio/Video Specialist

Morden, Manitoba CANADA