The15 PRO ACTIVE platform, The12 model offers much of the same performance in a smaller and more affordable footprint. The 12" point source axi-symmetric speaker has been designed as screen speaker for large theaters as left, center and right speaker or can be used for very large theaters as a surround bed speaker. The12 PRO ACTIVE EXT is an extremely impressive and extraordinary performing musical speaker system, that leaves nothing to be desired. The EXT designation signifies that the onboard DSP/Amplifier of The12 PRO ACTIVE version is instead placed in a rack, with options for power output and channel count, with speaker wires directly connecting them.