DBX Drive Rack
This is the best PA and pro sound investment I have ever made. Just had to tell you how wonderful this piece of equipment is. The Drive Rack PA is basically a crossover system with a built in pink noise calibration system. With just a few menu choices (and plugging in the calibrated microphone -- optional) the system sent pink noise through the PA speakers, and the system automatically EQ'd the 29 band graphic equalizer for a perfectly flat frequency response across the entire audio spectrum. My PA has never sounded better.
Bottom line: This gear will probably make even crappy speakers sound good.