EMF/RFI isolation with aluminum sheet metal

Hi all. I have my Class D power amps in pretty close proximity to my DirectTV DVR, both on the bottom shelf of a double wide built-in cabinet. I'm concerned about each component (the DVR and the amps) interfering with one another (EMF/RFI). One thought I had was to just cut a piece of sheet metal to size and place it in the cabinet between them. They are about 4 inches apart I can cut the sheet metal so it will basically be as if the entire area (cross-section) of the cabinet will be filled with only minimal gaps. Is this wortwhile? Any other ideas?

thanks!

--dan