Whereas most Bluetooth speakers are designed to be device-agnostic, Definitive Technology's Sound Cylinder ($199) is made to specifically complement the iPad and other tablets. The 2.1 channel speaker has midrange and high frequency drivers, plus a woofer that fires from the side of the tube. Your iPad can rest in the rubber holder at the top, with a pop-out stand holding it in a standing position. Physical controls are located on the other end of…