What kind of radio? Is this a replacement? Any similar problems with previous radio? Does it buzz when both the trailer is hooked up to 110 and only running on 12v
? Is your 110 polarity correct? What happens with only one speaker hooked up? Did you check your speakers are not hooked up out of phase (+ an - mismatch) Are you sure you have a good ground? Can you contact the manufacturer for a troubleshooting list?