Police and drivers get ready for Rumblers Din-filled times spur new device By Maria Cramer Globe Staff / May 19, 2008 Modern technology has been hard on the old-fashioned police siren. Drivers are pumping up the volume in their cars to earth-shaking decibels, chattering on their cellphones or texting their friends. Others are driving in cars so insulated from outside noise, they are practically sound-proof. Enter the Rumbler.