Off the top of my head an AudioControl DQS or DQT. Both would work, but the DQS offers 6 channels of EQ, the DQT only offers 2 channels, though you really only need the 2 channel to fiddle with the horns.
Horns are pretty picky about installation, as far as getting a good center image and good stage height. They need to be level in the vertical and horizontal axis, they also need to be even as far as distance to a single point. It isn't difficult, but I definitely wouldn't consider them a "set it and forget it" type driver. Definitely worth the work, but it can get a bit tricky.
Search on youtube for image dynamics, they have some good clips on horn basics.