The CM4 is a 21 /2 -way floor-standing speaker finished in a choice of two real wood veneers - Maple and Rosenut. The brushed aluminium baffle emphasises the clean, modern design approach. q The slim floor-standing CM4 adds extra bass extension as well as resolving fine detail, and can reach higher output levels for the larger room. Tube loading the tweeter ensures far greater absorption of unwanted radiation from the rear of the diaphragm. The resulting effect is to create a more focused and natural high frequency sound. The bass unit is made from aluminium, which was selected for its excellent stiffness and ability to function as a piston. Twin Flowports at the rear of the cabinet have surfaces dimpled like a golf ball to smooth the airflow and reduce turbulence. The lower Flowport is integrally moulded with the terminal tray. Technical highlights Nautilus™ Tweeter: B&W's Nautilus Tweeter technology ensures that the sound remains focused and time-sensitive and that the stereo-image is presented with unparalleled three dimensional accuracy. Kevlar®: B&W developed and patented the method of using Kevlar® for loudspeaker cones to reduce unwanted standing waves. DuPont originally created Kevlar® for use in bulletproof vests. Flowport™: Golf ball aerodynamics theory points the way towards lower distortion reflex ports. Dimples improve the way the air flows over the surface of any object. In the case of reflex ports, they offer a significant improvement over simply flaring the port ends in reducing air flow turbulence at each end of the port; so you get less chuffing noise and less compression at high sound levels.