1,200-watt High-definition 2-way Loudspeaker, Active, with 12" Woofer, 3" Voice Coil, 1.75" Compression Driver, Patented Acoustic-correction, and Birch Cabinet (each). In designing the HD1221, Mackie applied their time-proven principles of amplification toward a true high-definition design. To achieve this, Mackie added their patented acoustic correction processing along with transducer time-alignment and phase-correction technology, to develop an extremely accurate loudspeaker.