I built these speakers for my high school using the Kappa 15LFA and the PSD 2002 compression driver on an exponential horn... Very loud. The crossover needs tweaking, though. There isn't enough horn attenuation and it's too overbearing. I didn't see it as a problem at first, but after listening to them in use at the actual school in various settings, they need an adjustment. The crossover is virtually identical to Wayne's, except there isn't the HF compensation cap.

Adam