There is a DIY on the Club site http://hyundaicoupeclub.co.uk/viewtopic ... 042&p=2637 which will help you trace the source of your problem..

if you can eliminate it at the source rather than trying to supress it once it's in there you will have a better system.

what are the bigger problems??? cheers for your help Lidl

well they all amount to the head unit being broken, earth tracks going on the board and such..

there down opposite sides of the car.

Goin to try a new earth today and hopefully it will be sorted

Right tried the earth points, no difference. BUT further testing has shown that if both pairs of RCA's are pluged in then the noise is apparent, if only one pair is plugged in then there is no noise, and it dosen't matter which pair is taken out. I'm baffled. Could they be causing each other to make noise??? if so is there any solution to that???

Just to clear it up my system is this:
Alpine Headunit - 2/3 RCA's being used (rear speakers and Subwoofer)
One 4 Channel/4 RCA input Amp - Ch1+2 Bridged to make 1 channel for subwoofer
Ch3+4 powering 6x9's

RCA's run down DriverSide
Power and remote signal go down Nearside

There is also no difference if i turn the headunits onboard amp on or off