ground loop noise

lol gotcha =) thanks for the tips, will try them all in one by one tomorrow + post the results

alright, took a little longer than expected to try some solutions, but here is the update: [quote]1) cut the grounds for the speakers, shorted them to a good ground. 2) insulated the ends from radio.[/quote] this fixed the problem upon initial inspection. ground loop noise is completely gone, although the interference near the top of the volume knob is still clearly audible. for clarification sake, this isint a high pitched whine like before (correlating to engine rpm) but rather just plain old static. the noise at normal listening level is inaudible, and thus client is satisfied with this solution. HOWEVER. upon plugging the antenna back into the clarion HU, i find that the ground loop has not only returned, but has actually gotten significantly louder. what might cause a ground loop when antenna is plugged in?