Wharfedale DELTA-AXF12 2-Way Bi-Amplified Active Loudspeaker - 12″The active full range speaker models of the Wharfedale Pro Delta AX series are praised as a real insider tip. They are among the professional active loudspeakers and offer the professional a unique price performance ratio. The active PA speakers use a dual class D amplifier. These so called bi amp amplifiers are specially tailored to the drivers developed by Wharfedale Pro and offer optimum efficiency with the internal, active isolation. Each driver