I looked at frequency plots of the DX4 on open baffle and I inserted a simple inductor to flatten out the frequency response from about 500 hz and up. It does not even out the frequency anomolies in the 5 - 10 k range, but it does do a good job overall.

I high pass the DX4 using the coupling capacitor between the driver and output tube of my 300B SE amps.

The woofers I use are a set of 15 inch drivers Genesis uses with their subwoofers. I had one from a nonfunctioning subwoofer and a second which was a spare. These are mounted on the same baffle as the DX4s (in a sort of U-baffle). I also have a set of Avalanche 18 inch drivers on open baffle mounted in a W-baffle.

I crossover to the woofers at about 100 hz. I use a 500 watt/channel Hafler amp to drive the woofers.

Retsel