Hi Alex Weirdness reigns. It just didn't seem possible that the cabinet was causing the problem, so I removed the crossover completely, added length to the wires to the drivers, stuck them out the ports, and remeasured the tweeter and woofers. I imported all that into my file for the original design to see whether my crossover would produce the same awful results. Which it did. When I compared the new woofer measurements with my old ones, there was almost a 4 dB difference in output below 1kHz. Each woofer was almost 2 dB more efficient, which translates into a 4 dB gain when both are running in parallel. I have a different center design using the same cabinet and woofers, but the Fountek ribbon instead of the RAAL, and also the dome version of the ST center. I imported the new measurements into those files, and the same thing happened. Either Seas has changed the woofer parameters, or your particular ones are just strange. So I redid the crossover design to get flat response, which wasn't very difficult. I have to get ready to leave for RMAF tomorrow morning, so I won't get a chance to build the crossover until next week. Weird. Down-the-center-weird. Cheers, Dennis