We only built two cabinets like this and they are the prototypes for the Rat 5 system.  We still use them for side fills although the horns have been swapped out for conical waveguides. There actually was a tweeter in the box as well, but it was never used and eventually eliminated.  The physical size of the 2" horn did not leave enough room to fit a 1" horn, so we began the search/wait for a 2"/1" horn pair that would fit into the design.