Noisy lightbar

Hey guys I have a 52" curved Cree lightbar on my Chevy Silverado 2500 HD and even very low speeds like 10 or 15 miles an hour it Hums and vibrates a lot and it shakes the whole cab going down the highway and it’s very noisy any idea what I can do to stop that humming noise? Before this curved lightbar I had a straight 50 inch and it made a real high-pitched whining noise going down the highway very very annoying. Please help…… Thanks Rich